docs(02): capture phase context

.planning/phases/02-planning-threads/02-CONTEXT.md

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+# Phase 2: Planning Threads - Context
+
+**Gathered:** 2026-03-15
+**Status:** Ready for planning
+
+<domain>
+## Phase Boundary
+
+Purchase research workflow: create planning threads, add candidate products, compare them, and resolve a thread by picking a winner that moves into the collection. No setups, no dashboard, no impact preview — those are later phases or v2.
+
+</domain>
+
+<decisions>
+## Implementation Decisions
+
+### Thread List View
+- Card-based layout, same visual pattern as collection items
+- Thread card shows: name prominent, then pill/chip tags for candidate count, creation date, price range
+- Flat list, most recent first (no grouping)
+- Resolved/archived threads hidden by default with a toggle to show them
+
+### Candidate Display & Management
+- Candidates displayed as card grid within a thread (same card style as collection items)
+- Slide-out panel for adding/editing candidates (reuses existing SlideOutPanel component)
+- Candidates share the exact same fields as collection items: name, weight, price, category, notes, product link, image
+- Same data shape means resolution is seamless — candidate data maps directly to a collection item
+
+### Thread Resolution Flow
+- Picking a winner auto-creates a collection item from the candidate's data (no review/edit step)
+- Confirmation dialog before resolving ("Pick [X] as winner? This will add it to your collection.")
+- After resolution, thread is archived (removed from active list, kept in history)
+- Confirmation dialog reuses the existing ConfirmDialog component pattern
+
+### Navigation
+- Tab within the collection page: "My Gear" | "Planning" tabs
+- Top navigation bar always visible for switching between major sections
+- Thread list and collection share the same page with tab-based switching
+
+### Claude's Discretion
+- Exact "pick winner" UX (button on card vs thread-level action)
+- Thread detail page layout (how the thread view is structured beyond the card grid)
+- Empty state for threads (no threads yet) and empty thread (no candidates yet)
+- How the tab switching integrates with TanStack Router (query params vs nested routes)
+- Thread card image (first candidate's image, thread-specific image, or none)
+
+</decisions>
+
+<specifics>
+## Specific Ideas
+
+- Visual consistency is important — threads and candidates should look and feel like the collection, not a separate app
+- Pill/chip tag pattern carries over: candidate count, date, price range displayed as compact tags
+- The slide-out panel pattern from Phase 1 should be reused directly for candidate add/edit
+- Thread resolution is a one-step action: confirm → item appears in collection, thread archived
+
+</specifics>
+
+<code_context>
+## Existing Code Insights
+
+### Reusable Assets
+- `SlideOutPanel.tsx`: Right-side slide panel — reuse for candidate add/edit
+- `ConfirmDialog.tsx`: Confirmation modal — reuse for resolution confirmation
+- `ItemCard.tsx`: Card component with tag chips — pattern reference for thread/candidate cards
+- `ItemForm.tsx`: Form with category picker — candidate form shares the same fields
+- `CategoryPicker.tsx`: ARIA combobox — reuse for candidate category selection
+- `ImageUpload.tsx`: Image upload component — reuse for candidate images
+- `TotalsBar.tsx`: Sticky totals — could adapt for thread-level candidate totals
+
+### Established Patterns
+- Service layer with DB injection for testability (item.service.ts, category.service.ts)
+- Hono routes with Zod validation via @hono/zod-validator
+- TanStack Query hooks for data fetching (useItems, useCategories, useTotals)
+- Zustand store for UI state (uiStore.ts)
+- API client utilities (apiGet, apiPost, apiPut, apiDelete, apiUpload)
+- Shared Zod schemas in src/shared/schemas.ts
+- Weight stored in grams, price in cents (integer math)
+
+### Integration Points
+- Database: Need new tables for threads and thread_candidates (src/db/schema.ts)
+- Shared schemas: Need thread and candidate Zod schemas (src/shared/schemas.ts)
+- Server: New routes mounted in src/server/index.ts
+- Client: New route/tab integrated via TanStack Router
+- Resolution creates items via existing item.service.ts createItem function
+
+</code_context>
+
+<deferred>
+## Deferred Ideas
+
+- Linking existing collection items as reference candidates in a thread — nice-to-have, not v1
+- Side-by-side comparison view (columns instead of cards) — could be v2 enhancement (THRD-05)
+- Status tracking on candidates (researching → ordered → arrived) — v2 (THRD-06)
+- Impact preview showing how a candidate affects setup weight/cost — v2 (THRD-08)
+
+</deferred>
+
+---
+
+*Phase: 02-planning-threads*
+*Context gathered: 2026-03-15*