chore: add CLAUDE.md, initial Drizzle migration, and update gitignore

Add project instructions for Claude Code, the initial database migration,
and ignore the .claude/ local config directory.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -0,0 +1,70 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+GearBox is a single-user web app for managing gear collections (bikepacking, sim racing, etc.), tracking weight/price, and planning purchases through research threads. Full-stack TypeScript monolith running on Bun.
+
+## Commands
+
+```bash
+# Development (run both in separate terminals)
+bun run dev:client          # Vite dev server on :5173 (proxies /api to :3000)
+bun run dev:server          # Hono server on :3000 with hot reload
+
+# Database
+bun run db:generate         # Generate Drizzle migration from schema changes
+bun run db:push             # Apply migrations to gearbox.db
+
+# Testing
+bun test                    # Run all tests
+bun test tests/services/item.service.test.ts  # Run single test file
+
+# Lint & Format
+bun run lint                # Biome check (tabs, double quotes, organized imports)
+
+# Build
+bun run build               # Vite build → dist/client/
+```
+
+## Architecture
+
+**Stack**: React 19 + Hono + Drizzle ORM + SQLite, all running on Bun.
+
+### Client (`src/client/`)
+- **Routing**: TanStack Router with file-based routes in `src/client/routes/`. Route tree auto-generated to `routeTree.gen.ts` — never edit manually.
+- **Data fetching**: TanStack React Query via custom hooks in `src/client/hooks/` (e.g., `useItems`, `useThreads`, `useSetups`). Mutations invalidate related query keys.
+- **UI state**: Zustand store (`stores/uiStore.ts`) for panel/dialog state only — server data lives in React Query.
+- **API calls**: Thin fetch wrapper in `lib/api.ts` (`apiGet`, `apiPost`, `apiPut`, `apiDelete`, `apiUpload`).
+- **Styling**: Tailwind CSS v4.
+
+### Server (`src/server/`)
+- **Routes** (`routes/`): Hono handlers with Zod validation via `@hono/zod-validator`. Delegate to services.
+- **Services** (`services/`): Pure business logic functions that take a db instance. No HTTP awareness — testable without mocking.
+- Route registration in `src/server/index.ts` via `app.route("/api/...", routes)`.
+
+### Shared (`src/shared/`)
+- **`schemas.ts`**: Zod schemas for API request validation (source of truth for types).
+- **`types.ts`**: Types inferred from Zod schemas + Drizzle table definitions. No manual type duplication.
+
+### Database (`src/db/`)
+- **Schema**: `schema.ts` — Drizzle table definitions for SQLite.
+- **Prices stored as cents** (`priceCents: integer`) to avoid float rounding.
+- **Timestamps**: stored as integers (unix epoch) with `{ mode: "timestamp" }`.
+- Tables: `categories`, `items`, `threads`, `threadCandidates`, `setups`, `setupItems`, `settings`.
+
+### Testing (`tests/`)
+- Bun test runner. Tests at service level and route level.
+- `tests/helpers/db.ts`: `createTestDb()` creates in-memory SQLite with full schema and seeds an "Uncategorized" category. When adding schema columns, update both `src/db/schema.ts` and the test helper's CREATE TABLE statements.
+
+## Path Alias
+
+`@/*` maps to `./src/*` (configured in tsconfig.json).
+
+## Key Patterns
+
+- **Thread resolution**: Resolving a thread copies the winning candidate's data into a new item in the collection, sets `resolvedCandidateId`, and changes status to "resolved".
+- **Setup item sync**: `PUT /api/setups/:id/items` replaces all setup_items atomically (delete all, re-insert).
+- **Image uploads**: `POST /api/images` saves to `./uploads/` with UUID filename, returned as `imageFilename` on item/candidate records.
+- **Aggregates** (weight/cost totals): Computed via SQL on read, not stored on records.