# Phase 1: Foundation and Collection - Research

**Researched:** 2026-03-14
**Domain:** Full-stack web app scaffolding, SQLite CRUD, React SPA with collection management
**Confidence:** HIGH

## Summary

Phase 1 is a greenfield build establishing the entire project stack: Bun runtime with Hono API server, React 19 SPA via Vite with TanStack Router, Drizzle ORM over bun:sqlite, and Tailwind v4 styling. The phase delivers complete gear collection CRUD (items and categories) with aggregate weight/cost totals, a slide-out panel for add/edit, a card grid grouped by category, and a first-run onboarding wizard.

The critical architectural decision is using **Vite as the frontend dev server** (required by TanStack Router's file-based routing plugin) with **Hono on Bun as the backend**, connected via Vite's dev proxy. This is NOT Bun's native fullstack HTML entrypoint pattern -- TanStack Router requires the Vite plugin, which means Vite owns the frontend build pipeline. In production, Hono serves the Vite-built static assets alongside API routes from a single Bun process.

A key blocker from STATE.md has been resolved: `@hono/zod-validator` now supports Zod 4 (merged May 2025, PR #1173). The project can use Zod 4.x without pinning to 3.x.

**Primary recommendation:** Scaffold with Vite + TanStack Router for frontend, Hono + Drizzle on Bun for backend, with categories as a first-class table (not just a text field on items) to support emoji icons, rename, and delete-with-reassignment.

<user_constraints>

## User Constraints (from CONTEXT.md)

### Locked Decisions
- Card grid layout, grouped by category headers
- Each card shows: item name (prominent), then tag-style chips for weight, price, and category
- Item image displayed on the card for visual identification
- Items grouped under category headers with per-category weight/cost subtotals
- Global sticky totals bar at the top showing total items, weight, and cost
- Empty categories are hidden from the collection view
- Slide-out panel from the right side for both adding and editing items
- Same panel component for add (empty) and edit (pre-filled)
- Collection remains visible behind the panel for context
- Confirmation dialog before deleting items
- Single-level categories only (no subcategories)
- Searchable category picker in the item form -- type to find existing or create new
- Categories editable from the collection overview (rename, delete, change icon)
- Each category gets an emoji/icon for visual distinction
- Deleting a category moves its items to "Uncategorized" default category
- Step-by-step onboarding wizard for first-time users (guides through: create first category, add first item)
- Cards should feel clean and minimal -- "light and airy" aesthetic
- Item info displayed as tag-style chips (compact, scannable)
- Category picker works like a combobox: type to search, select existing, or create new inline
- Photos on cards are important for visual identification even in v1

### Claude's Discretion
- Form layout for item add/edit panel (all fields visible vs grouped sections)
- Loading states and skeleton design
- Exact spacing, typography, and Tailwind styling choices
- Error state handling and validation feedback
- Weight unit storage (grams internally, display in user's preferred unit can be deferred to v2)

### Deferred Ideas (OUT OF SCOPE)
- Subcategories (e.g. "Bags" -> "Handlebar Bag")
- Full photo management is v2 (basic image upload for cards IS in scope)

</user_constraints>

<phase_requirements>

## Phase Requirements

| ID | Description | Research Support |
|----|-------------|-----------------|
| COLL-01 | User can add gear items with name, weight, price, category, notes, and product link | Drizzle schema for items table, Hono POST endpoint, React slide-out panel with Zod-validated form, image upload to local filesystem |
| COLL-02 | User can edit and delete gear items | Hono PUT/DELETE endpoints, same slide-out panel pre-filled for edit, confirmation dialog for delete, image cleanup on item delete |
| COLL-03 | User can organize items into user-defined categories | Separate categories table with emoji field, combobox category picker, category CRUD endpoints, "Uncategorized" default category, reassignment on category delete |
| COLL-04 | User can see automatic weight and cost totals by category and overall | SQL SUM aggregates via Drizzle, computed on read (never cached), sticky totals bar component, per-category subtotals in group headers |

</phase_requirements>

## Standard Stack

### Core
| Library | Version | Purpose | Why Standard |
|---------|---------|---------|--------------|
| Bun | 1.3.x | Runtime, package manager | Built-in SQLite, native TS, fast installs |
| React | 19.2.x | UI framework | Locked in CONTEXT.md |
| Vite | 8.x | Frontend dev server + production builds | Required by TanStack Router plugin for file-based routing |
| Hono | 4.12.x | Backend API framework | Web Standards, first-class Bun support, tiny footprint |
| Drizzle ORM | 0.45.x | Database ORM + migrations | Type-safe SQL, native bun:sqlite driver, built-in migration tooling |
| Tailwind CSS | 4.2.x | Styling | CSS-native config, auto content detection, microsecond incremental builds |
| TanStack Router | 1.x | Client-side routing | Type-safe routing with file-based route generation via Vite plugin |
| TanStack Query | 5.x | Server state management | Handles fetching, caching, cache invalidation on mutations |
| Zustand | 5.x | Client state management | UI state: panel open/close, active filters, onboarding step |
| Zod | 4.x | Schema validation | Shared between client forms and Hono API validation. Zod 4 confirmed compatible with @hono/zod-validator (PR #1173, May 2025) |
| TypeScript | 5.x | Type safety | Bun transpiles natively, required by Drizzle and TanStack Router |

### Supporting
| Library | Version | Purpose | When to Use |
|---------|---------|---------|-------------|
| @tanstack/router-plugin | latest | Vite plugin for file-based routing | Required in vite.config.ts, must be listed BEFORE @vitejs/plugin-react |
| @hono/zod-validator | 0.7.6+ | Request validation middleware | Validate API request bodies/params using Zod schemas |
| drizzle-kit | latest | DB migrations CLI | `bunx drizzle-kit generate` and `bunx drizzle-kit push` for schema changes |
| clsx | 2.x | Conditional class names | Building components with variant styles |
| @vitejs/plugin-react | latest (Vite 8 compatible) | React HMR/JSX | Required in vite.config.ts for Fast Refresh |
| @tailwindcss/vite | latest | Tailwind Vite plugin | Required in vite.config.ts for Tailwind v4 |
| @biomejs/biome | latest | Linter + formatter | Single tool replacing ESLint + Prettier |

### Alternatives Considered
| Instead of | Could Use | Tradeoff |
|------------|-----------|----------|
| Vite + Hono | Bun fullstack (HTML entrypoints) | Bun fullstack is simpler but incompatible with TanStack Router file-based routing which requires the Vite plugin |
| Zod 4.x | Zod 3.23.x | No need to pin -- @hono/zod-validator supports Zod 4 as of May 2025 |
| Separate categories table | Category as text field on items | Text field cannot store emoji/icon, cannot rename without updating all items, cannot enforce "Uncategorized" default cleanly |

**Installation:**
```bash
# Initialize
bun init

# Core frontend
bun add react react-dom @tanstack/react-router @tanstack/react-query zustand zod clsx

# Core backend
bun add hono @hono/zod-validator drizzle-orm

# Styling
bun add tailwindcss @tailwindcss/vite

# Build tooling
bun add -d vite @vitejs/plugin-react @tanstack/router-plugin typescript @types/react @types/react-dom

# Database tooling
bun add -d drizzle-kit

# Linting + formatting
bun add -d @biomejs/biome

# Dev tools
bun add -d @tanstack/react-query-devtools @tanstack/react-router-devtools
```

## Architecture Patterns

### Recommended Project Structure
```
src/
  client/                # React SPA (Vite entry point)
    routes/              # TanStack Router file-based routes
      __root.tsx         # Root layout with sticky totals bar
      index.tsx          # Collection page (default route)
    components/          # Shared UI components
      ItemCard.tsx       # Gear item card with chips
      CategoryHeader.tsx # Category group header with subtotals
      SlideOutPanel.tsx  # Right slide-out panel for add/edit
      CategoryPicker.tsx # Combobox: search, select, or create category
      TotalsBar.tsx      # Sticky global totals bar
      OnboardingWizard.tsx # First-run step-by-step guide
      ConfirmDialog.tsx  # Delete confirmation
    hooks/               # TanStack Query hooks
      useItems.ts        # CRUD operations for items
      useCategories.ts   # CRUD operations for categories
      useTotals.ts       # Aggregate totals query
    stores/              # Zustand stores
      uiStore.ts         # Panel state, onboarding state
    lib/                 # Client utilities
      api.ts             # Fetch wrapper for API calls
      formatters.ts      # Weight/cost display formatting
  server/                # Hono API server
    index.ts             # Hono app instance, route registration
    routes/              # API route handlers
      items.ts           # /api/items CRUD
      categories.ts      # /api/categories CRUD
      totals.ts          # /api/totals aggregates
      images.ts          # /api/images upload
    services/            # Business logic
      item.service.ts    # Item CRUD logic
      category.service.ts # Category management with reassignment
  db/                    # Database layer
    schema.ts            # Drizzle table definitions
    index.ts             # Database connection singleton (WAL mode, foreign keys)
    seed.ts              # Seed "Uncategorized" default category
    migrations/          # Drizzle Kit generated migrations
  shared/                # Zod schemas shared between client and server
    schemas.ts           # Item, category validation schemas
    types.ts             # Inferred TypeScript types
public/                  # Static assets
uploads/                 # Gear photos (gitignored)
index.html               # Vite SPA entry point
vite.config.ts           # Vite + TanStack Router plugin + Tailwind plugin
drizzle.config.ts        # Drizzle Kit config
```

### Pattern 1: Vite Frontend + Hono Backend (Dev Proxy)
**What:** Vite runs the frontend dev server with HMR. Hono runs on Bun as the API server on a separate port. Vite's `server.proxy` forwards `/api/*` to Hono. In production, Hono serves Vite's built output as static files.
**When to use:** When TanStack Router (or any Vite plugin) is required for the frontend.
**Example:**
```typescript
// vite.config.ts
import { defineConfig } from "vite";
import react from "@vitejs/plugin-react";
import tailwindcss from "@tailwindcss/vite";
import { tanstackRouter } from "@tanstack/router-plugin/vite";

export default defineConfig({
  plugins: [
    tanstackRouter({ target: "react", autoCodeSplitting: true }),
    react(),
    tailwindcss(),
  ],
  server: {
    proxy: {
      "/api": "http://localhost:3000",
      "/uploads": "http://localhost:3000",
    },
  },
  build: {
    outDir: "dist/client",
  },
});
```

```typescript
// src/server/index.ts
import { Hono } from "hono";
import { serveStatic } from "hono/bun";
import { itemRoutes } from "./routes/items";
import { categoryRoutes } from "./routes/categories";

const app = new Hono();

// API routes
app.route("/api/items", itemRoutes);
app.route("/api/categories", categoryRoutes);

// Serve uploaded images
app.use("/uploads/*", serveStatic({ root: "./" }));

// Serve Vite-built SPA in production
if (process.env.NODE_ENV === "production") {
  app.use("/*", serveStatic({ root: "./dist/client" }));
  app.get("*", serveStatic({ path: "./dist/client/index.html" }));
}

export default { port: 3000, fetch: app.fetch };
```

### Pattern 2: Categories as a First-Class Table
**What:** Categories are a separate table with id, name, and emoji fields. Items reference categories via foreign key. An "Uncategorized" category with a known ID (1) is seeded on DB init.
**When to use:** When categories need independent properties (emoji/icon), rename support, and delete-with-reassignment.
**Example:**
```typescript
// db/schema.ts
import { sqliteTable, text, integer, real } from "drizzle-orm/sqlite-core";

export const categories = sqliteTable("categories", {
  id: integer("id").primaryKey({ autoIncrement: true }),
  name: text("name").notNull().unique(),
  emoji: text("emoji").notNull().default("📦"),
  createdAt: integer("created_at", { mode: "timestamp" }).notNull()
    .$defaultFn(() => new Date()),
});

export const items = sqliteTable("items", {
  id: integer("id").primaryKey({ autoIncrement: true }),
  name: text("name").notNull(),
  weightGrams: real("weight_grams"),
  priceCents: integer("price_cents"),
  categoryId: integer("category_id").notNull().references(() => categories.id),
  notes: text("notes"),
  productUrl: text("product_url"),
  imageFilename: text("image_filename"),
  createdAt: integer("created_at", { mode: "timestamp" }).notNull()
    .$defaultFn(() => new Date()),
  updatedAt: integer("updated_at", { mode: "timestamp" }).notNull()
    .$defaultFn(() => new Date()),
});
```

### Pattern 3: Slide-Out Panel with Shared Component
**What:** A single `SlideOutPanel` component serves both add and edit flows. When adding, fields are empty. When editing, fields are pre-filled from the existing item. The panel slides in from the right, overlaying (not replacing) the collection view.
**When to use:** Per CONTEXT.md locked decision.
**State management:**
```typescript
// stores/uiStore.ts
import { create } from "zustand";

interface UIState {
  panelMode: "closed" | "add" | "edit";
  editingItemId: number | null;
  openAddPanel: () => void;
  openEditPanel: (itemId: number) => void;
  closePanel: () => void;
}

export const useUIStore = create<UIState>((set) => ({
  panelMode: "closed",
  editingItemId: null,
  openAddPanel: () => set({ panelMode: "add", editingItemId: null }),
  openEditPanel: (itemId) => set({ panelMode: "edit", editingItemId: itemId }),
  closePanel: () => set({ panelMode: "closed", editingItemId: null }),
}));
```

### Pattern 4: Computed Totals (Never Cached)
**What:** Weight and cost totals are computed on every read via SQL aggregates. Never store totals as columns.
**Why:** Avoids stale data bugs when items are added, edited, or deleted.
**Example:**
```typescript
// server/services/item.service.ts
import { db } from "../../db";
import { items, categories } from "../../db/schema";
import { eq, sql } from "drizzle-orm";

export function getCategoryTotals() {
  return db
    .select({
      categoryId: items.categoryId,
      categoryName: categories.name,
      categoryEmoji: categories.emoji,
      totalWeight: sql<number>`COALESCE(SUM(${items.weightGrams}), 0)`,
      totalCost: sql<number>`COALESCE(SUM(${items.priceCents}), 0)`,
      itemCount: sql<number>`COUNT(*)`,
    })
    .from(items)
    .innerJoin(categories, eq(items.categoryId, categories.id))
    .groupBy(items.categoryId)
    .all();
}

export function getGlobalTotals() {
  return db
    .select({
      totalWeight: sql<number>`COALESCE(SUM(${items.weightGrams}), 0)`,
      totalCost: sql<number>`COALESCE(SUM(${items.priceCents}), 0)`,
      itemCount: sql<number>`COUNT(*)`,
    })
    .from(items)
    .get();
}
```

### Anti-Patterns to Avoid
- **Storing money as floats:** Use integer cents (`priceCents`). Format to dollars only in the display layer. `0.1 + 0.2 !== 0.3` in JavaScript.
- **Category as a text field on items:** Cannot store emoji, cannot rename without updating all items, cannot enforce default category on delete.
- **Caching totals in the database:** Always compute from source data. SQLite SUM() over hundreds of items is sub-millisecond.
- **Absolute paths for images:** Store relative paths only (`uploads/{filename}`). Absolute paths break on deployment or directory changes.
- **Requiring all fields to add an item:** Only require `name`. Weight, price, category, etc. should be optional. Users fill in details over time.

## Don't Hand-Roll

| Problem | Don't Build | Use Instead | Why |
|---------|-------------|-------------|-----|
| Database migrations | Custom SQL scripts | Drizzle Kit (`drizzle-kit generate/push`) | Migration ordering, conflict detection, rollback support |
| Form validation | Manual if/else checks | Zod schemas shared between client and server | Single source of truth, type inference, consistent error messages |
| API data fetching/caching | useState + useEffect + fetch | TanStack Query hooks | Handles loading/error states, cache invalidation, refetching, deduplication |
| Combobox/autocomplete | Custom input with dropdown | Headless UI pattern (build from primitives with proper ARIA) or a lightweight combobox library | Keyboard navigation, screen reader support, focus management are deceptively hard |
| Slide-out panel animation | CSS transitions from scratch | Tailwind `transition-transform` + `translate-x` utilities | Consistent timing, GPU-accelerated, respects prefers-reduced-motion |
| Image resizing on upload | Custom canvas manipulation | Sharp library or accept-and-store (resize deferred to v2) | Sharp handles EXIF rotation, format conversion, memory management |

**Key insight:** For Phase 1, defer image resizing/thumbnailing. Accept and store the uploaded image as-is. Thumbnail generation can be added in v2 without schema changes (imageFilename stays the same, just generate a thumb variant).

## Common Pitfalls

### Pitfall 1: Bun Fullstack vs Vite Confusion
**What goes wrong:** Attempting to use Bun's native `Bun.serve()` with HTML entrypoints AND TanStack Router, which requires Vite's build pipeline.
**Why it happens:** Bun's fullstack dev server is compelling but incompatible with TanStack Router's file-based routing Vite plugin.
**How to avoid:** Use Vite for frontend (with TanStack Router plugin). Use Hono on Bun for backend. Connect via Vite proxy in dev, static file serving in prod.
**Warning signs:** Import errors from `@tanstack/router-plugin/vite`, missing route tree generation file.

### Pitfall 2: Category Delete Without Reassignment
**What goes wrong:** Deleting a category with foreign key constraints either fails (FK violation) or cascades (deletes all items in that category).
**Why it happens:** Using `ON DELETE CASCADE` or not handling FK constraints at all.
**How to avoid:** Before deleting a category, reassign all its items to the "Uncategorized" default category (id=1). Then delete. This is a two-step transaction.
**Warning signs:** FK constraint errors on category delete, or silent item deletion.

### Pitfall 3: Onboarding State Persistence
**What goes wrong:** User completes onboarding, refreshes the page, and sees the wizard again.
**Why it happens:** Storing onboarding completion state only in Zustand (memory). State is lost on page refresh.
**How to avoid:** Store `onboardingComplete` as a flag in SQLite (a simple `settings` table or a dedicated endpoint). Check on app load.
**Warning signs:** Onboarding wizard appears on every fresh page load.

### Pitfall 4: Image Upload Without Cleanup
**What goes wrong:** Deleting an item leaves its image file on disk. Over time, orphaned images accumulate.
**Why it happens:** DELETE endpoint removes the DB record but forgets to unlink the file.
**How to avoid:** In the item delete service, check `imageFilename`, unlink the file from `uploads/` before or after DB delete. Wrap in try/catch -- file missing is not an error worth failing the delete over.
**Warning signs:** `uploads/` directory grows larger than expected, files with no matching item records.

### Pitfall 5: TanStack Router Plugin Order in Vite Config
**What goes wrong:** File-based routes are not generated, `routeTree.gen.ts` is missing or stale.
**Why it happens:** TanStack Router plugin must be listed BEFORE `@vitejs/plugin-react` in the Vite plugins array.
**How to avoid:** Always order: `tanstackRouter()`, then `react()`, then `tailwindcss()`.
**Warning signs:** Missing `routeTree.gen.ts`, type errors on route imports.

### Pitfall 6: Forgetting PRAGMA foreign_keys = ON
**What goes wrong:** Foreign key constraints between items and categories are silently ignored. Items can reference non-existent categories.
**Why it happens:** SQLite has foreign key support but it is OFF by default. Must be enabled per connection.
**How to avoid:** Run `PRAGMA foreign_keys = ON` immediately after opening the database connection, before any queries.
**Warning signs:** Items with categoryId pointing to deleted categories, no errors on invalid inserts.

## Code Examples

### Database Connection Singleton
```typescript
// src/db/index.ts
import { Database } from "bun:sqlite";
import { drizzle } from "drizzle-orm/bun-sqlite";
import * as schema from "./schema";

const sqlite = new Database("gearbox.db");
sqlite.run("PRAGMA journal_mode = WAL");
sqlite.run("PRAGMA foreign_keys = ON");

export const db = drizzle(sqlite, { schema });
```

### Drizzle Config
```typescript
// drizzle.config.ts
import { defineConfig } from "drizzle-kit";

export default defineConfig({
  out: "./drizzle",
  schema: "./src/db/schema.ts",
  dialect: "sqlite",
  dbCredentials: {
    url: "gearbox.db",
  },
});
```

### Shared Zod Schemas
```typescript
// src/shared/schemas.ts
import { z } from "zod";

export const createItemSchema = z.object({
  name: z.string().min(1, "Name is required"),
  weightGrams: z.number().nonnegative().optional(),
  priceCents: z.number().int().nonnegative().optional(),
  categoryId: z.number().int().positive(),
  notes: z.string().optional(),
  productUrl: z.string().url().optional().or(z.literal("")),
});

export const updateItemSchema = createItemSchema.partial().extend({
  id: z.number().int().positive(),
});

export const createCategorySchema = z.object({
  name: z.string().min(1, "Category name is required"),
  emoji: z.string().min(1).max(4).default("📦"),
});

export const updateCategorySchema = z.object({
  id: z.number().int().positive(),
  name: z.string().min(1).optional(),
  emoji: z.string().min(1).max(4).optional(),
});

export type CreateItem = z.infer<typeof createItemSchema>;
export type UpdateItem = z.infer<typeof updateItemSchema>;
export type CreateCategory = z.infer<typeof createCategorySchema>;
```

### Hono Item Routes with Zod Validation
```typescript
// src/server/routes/items.ts
import { Hono } from "hono";
import { zValidator } from "@hono/zod-validator";
import { createItemSchema, updateItemSchema } from "../../shared/schemas";
import { db } from "../../db";
import { items } from "../../db/schema";
import { eq } from "drizzle-orm";

const app = new Hono();

app.get("/", async (c) => {
  const allItems = db.select().from(items).all();
  return c.json(allItems);
});

app.post("/", zValidator("json", createItemSchema), async (c) => {
  const data = c.req.valid("json");
  const result = db.insert(items).values(data).returning().get();
  return c.json(result, 201);
});

app.put("/:id", zValidator("json", updateItemSchema), async (c) => {
  const id = Number(c.req.param("id"));
  const data = c.req.valid("json");
  const result = db.update(items).set({ ...data, updatedAt: new Date() })
    .where(eq(items.id, id)).returning().get();
  if (!result) return c.json({ error: "Item not found" }, 404);
  return c.json(result);
});

app.delete("/:id", async (c) => {
  const id = Number(c.req.param("id"));
  // Clean up image file if exists
  const item = db.select().from(items).where(eq(items.id, id)).get();
  if (!item) return c.json({ error: "Item not found" }, 404);
  if (item.imageFilename) {
    try { await Bun.file(`uploads/${item.imageFilename}`).exists() &&
      await Bun.$`rm uploads/${item.imageFilename}`; } catch {}
  }
  db.delete(items).where(eq(items.id, id)).run();
  return c.json({ success: true });
});

export { app as itemRoutes };
```

### TanStack Query Hook for Items
```typescript
// src/client/hooks/useItems.ts
import { useQuery, useMutation, useQueryClient } from "@tanstack/react-query";
import type { CreateItem, UpdateItem } from "../../shared/schemas";

const API = "/api/items";

export function useItems() {
  return useQuery({
    queryKey: ["items"],
    queryFn: async () => {
      const res = await fetch(API);
      if (!res.ok) throw new Error("Failed to fetch items");
      return res.json();
    },
  });
}

export function useCreateItem() {
  const queryClient = useQueryClient();
  return useMutation({
    mutationFn: async (data: CreateItem) => {
      const res = await fetch(API, {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify(data),
      });
      if (!res.ok) throw new Error("Failed to create item");
      return res.json();
    },
    onSuccess: () => {
      queryClient.invalidateQueries({ queryKey: ["items"] });
      queryClient.invalidateQueries({ queryKey: ["totals"] });
    },
  });
}
```

### Seed Default Category
```typescript
// src/db/seed.ts
import { db } from "./index";
import { categories } from "./schema";

export function seedDefaults() {
  const existing = db.select().from(categories).all();
  if (existing.length === 0) {
    db.insert(categories).values({
      name: "Uncategorized",
      emoji: "📦",
    }).run();
  }
}
```

## State of the Art

| Old Approach | Current Approach | When Changed | Impact |
|--------------|------------------|--------------|--------|
| Zod 3.x + @hono/zod-validator | Zod 4.x fully supported | May 2025 (PR #1173) | No need to pin Zod 3.x. Resolves STATE.md blocker. |
| Tailwind config via JS | Tailwind v4 CSS-native config | Jan 2025 | No tailwind.config.js file. Theme defined in CSS via @theme directive. |
| Vite 7 (esbuild/Rollup) | Vite 8 (Rolldown-based) | 2025 | 5-30x faster builds. Same config API. |
| React Router v6/v7 | TanStack Router v1 | 2024 | Type-safe params, file-based routes, better SPA experience |
| bun:sqlite manual SQL | Drizzle ORM 0.45.x | Ongoing | Type-safe queries, migration tooling, schema-as-code |

**Deprecated/outdated:**
- `tailwind.config.js`: Use CSS `@theme` directive in Tailwind v4
- `better-sqlite3`: Use `bun:sqlite` (built-in, 3-6x faster)
- Vite `server.proxy` syntax: Verify correct format for Vite 8 (string shorthand still works)

## Open Questions

1. **Image upload size limit and accepted formats**
   - What we know: CONTEXT.md says photos on cards are important for visual identification
   - What's unclear: Maximum file size, accepted formats (jpg/png/webp), whether to resize on upload or defer to v2
   - Recommendation: Accept jpg/png/webp up to 5MB. Store as-is in `uploads/`. Defer resizing/thumbnailing to v2. Use `object-fit: cover` in CSS for consistent card display.

2. **Onboarding wizard scope**
   - What we know: Step-by-step guide through "create first category, add first item"
   - What's unclear: Exact number of steps, whether it is a modal overlay or a full-page takeover
   - Recommendation: 2-3 step modal overlay. Step 1: Welcome + create first category (with emoji picker). Step 2: Add first item to that category. Step 3: Done, show collection. Store completion flag in a `settings` table.

3. **Weight input UX**
   - What we know: Store grams internally. Display unit deferred to v2.
   - What's unclear: Should the input field accept grams only, or allow free-text with unit suffix?
   - Recommendation: For v1, use a numeric input labeled "Weight (g)". Clean and simple. V2 adds unit selector.

## Validation Architecture

### Test Framework
| Property | Value |
|----------|-------|
| Framework | Bun test runner (built-in, Jest-compatible API) |
| Config file | None needed (Bun detects test files automatically) |
| Quick run command | `bun test --bail` |
| Full suite command | `bun test` |

### Phase Requirements -> Test Map
| Req ID | Behavior | Test Type | Automated Command | File Exists? |
|--------|----------|-----------|-------------------|-------------|
| COLL-01 | Create item with all fields | unit | `bun test tests/services/item.service.test.ts -t "create"` | No - Wave 0 |
| COLL-01 | POST /api/items validates input | integration | `bun test tests/routes/items.test.ts -t "create"` | No - Wave 0 |
| COLL-02 | Update item fields | unit | `bun test tests/services/item.service.test.ts -t "update"` | No - Wave 0 |
| COLL-02 | Delete item cleans up image | unit | `bun test tests/services/item.service.test.ts -t "delete"` | No - Wave 0 |
| COLL-03 | Create/rename/delete category | unit | `bun test tests/services/category.service.test.ts` | No - Wave 0 |
| COLL-03 | Delete category reassigns items to Uncategorized | unit | `bun test tests/services/category.service.test.ts -t "reassign"` | No - Wave 0 |
| COLL-04 | Compute per-category totals | unit | `bun test tests/services/totals.test.ts -t "category"` | No - Wave 0 |
| COLL-04 | Compute global totals | unit | `bun test tests/services/totals.test.ts -t "global"` | No - Wave 0 |

### Sampling Rate
- **Per task commit:** `bun test --bail`
- **Per wave merge:** `bun test`
- **Phase gate:** Full suite green before `/gsd:verify-work`

### Wave 0 Gaps
- [ ] `tests/services/item.service.test.ts` -- covers COLL-01, COLL-02
- [ ] `tests/services/category.service.test.ts` -- covers COLL-03
- [ ] `tests/services/totals.test.ts` -- covers COLL-04
- [ ] `tests/routes/items.test.ts` -- integration tests for item API endpoints
- [ ] `tests/routes/categories.test.ts` -- integration tests for category API endpoints
- [ ] `tests/helpers/db.ts` -- shared test helper: in-memory SQLite instance with migrations applied
- [ ] Biome config: `bunx @biomejs/biome init`

## Sources

### Primary (HIGH confidence)
- [Bun fullstack dev server docs](https://bun.com/docs/bundler/fullstack) -- HTML entrypoints, Bun.serve() route config
- [Hono + Bun getting started](https://hono.dev/docs/getting-started/bun) -- fetch handler pattern, static file serving
- [Drizzle ORM + bun:sqlite setup](https://orm.drizzle.team/docs/get-started/bun-sqlite-new) -- schema, config, migrations
- [TanStack Router + Vite installation](https://tanstack.com/router/v1/docs/framework/react/installation/with-vite) -- plugin setup, file-based routing config
- [@hono/zod-validator Zod 4 support](https://github.com/honojs/middleware/issues/1148) -- PR #1173 merged May 2025, confirmed working

### Secondary (MEDIUM confidence)
- [Bun + React + Hono full-stack pattern](https://dev.to/falconz/serving-a-react-app-and-hono-api-together-with-bun-1gfg) -- project structure, proxy/static serving pattern
- [Tailwind CSS v4 blog](https://tailwindcss.com/blog/tailwindcss-v4) -- CSS-native config, @theme directive

### Tertiary (LOW confidence)
- Image upload best practices for Bun -- needs validation during implementation (file size limits, multipart handling)

## Metadata

**Confidence breakdown:**
- Standard stack: HIGH -- all libraries verified via official docs, version compatibility confirmed, Zod 4 blocker resolved
- Architecture: HIGH -- Vite + Hono pattern well-documented, TanStack Router plugin requirement verified
- Pitfalls: HIGH -- drawn from PITFALLS.md research and verified against stack specifics
- Database schema: HIGH -- Drizzle + bun:sqlite pattern verified via official docs

**Research date:** 2026-03-14
**Valid until:** 2026-04-14 (stable ecosystem, no fast-moving dependencies)