docs(03-01): complete setup backend plan

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

.planning/phases/03-setups-and-dashboard/03-01-SUMMARY.md

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+---
+phase: 03-setups-and-dashboard
+plan: 01
+subsystem: api
+tags: [drizzle, hono, sqlite, junction-table, tdd]
+
+requires:
+  - phase: 01-collection-core
+    provides: items table, categories table, item service pattern, route pattern, test helper
+provides:
+  - Setup CRUD API at /api/setups
+  - Junction table setup_items (many-to-many items-to-setups)
+  - SQL aggregation for setup totals (weight, cost, item count)
+  - syncSetupItems for batch item assignment
+affects: [03-02-setup-frontend, 03-03-dashboard]
+
+tech-stack:
+  added: []
+  patterns: [junction-table-with-cascade, sql-coalesce-aggregation, delete-all-reinsert-sync]
+
+key-files:
+  created:
+    - src/server/services/setup.service.ts
+    - src/server/routes/setups.ts
+    - tests/services/setup.service.test.ts
+    - tests/routes/setups.test.ts
+  modified:
+    - src/db/schema.ts
+    - src/shared/schemas.ts
+    - src/shared/types.ts
+    - src/server/index.ts
+    - tests/helpers/db.ts
+
+key-decisions:
+  - "syncSetupItems uses delete-all + re-insert in transaction for simplicity over diff-based sync"
+  - "SQL COALESCE ensures 0 returned for empty setups instead of null"
+
+patterns-established:
+  - "Junction table pattern: cascade deletes on both FK sides for clean removal"
+  - "Sync pattern: transactional delete-all + re-insert for many-to-many updates"
+
+requirements-completed: [SETP-01, SETP-02, SETP-03]
+
+duration: 8min
+completed: 2026-03-15
+---
+
+# Phase 3 Plan 1: Setup Backend Summary
+
+**Setup CRUD API with junction table, SQL aggregation for totals, and transactional item sync**
+
+## Performance
+
+- **Duration:** 8 min
+- **Started:** 2026-03-15T11:35:17Z
+- **Completed:** 2026-03-15T11:43:11Z
+- **Tasks:** 2 (TDD RED + GREEN)
+- **Files modified:** 9
+
+## Accomplishments
+- Setup CRUD with all 7 API endpoints working
+- Junction table (setup_items) with cascade deletes on both setup and item deletion
+- SQL aggregation returning itemCount, totalWeight, totalCost via COALESCE subqueries
+- Full TDD with 24 new tests (13 service + 11 route), all 87 tests passing
+
+## Task Commits
+
+Each task was committed atomically:
+
+1. **Task 1: RED - Failing tests + schema** - `1e4e74f` (test)
+2. **Task 2: GREEN - Implementation** - `0f115a2` (feat)
+
+## Files Created/Modified
+- `src/db/schema.ts` - Added setups and setupItems table definitions
+- `src/shared/schemas.ts` - Added createSetupSchema, updateSetupSchema, syncSetupItemsSchema
+- `src/shared/types.ts` - Added CreateSetup, UpdateSetup, SyncSetupItems, Setup, SetupItem types
+- `src/server/services/setup.service.ts` - Setup business logic with DB injection
+- `src/server/routes/setups.ts` - Hono API routes for all 7 setup endpoints
+- `src/server/index.ts` - Mounted setupRoutes at /api/setups
+- `tests/helpers/db.ts` - Added setups and setup_items CREATE TABLE statements
+- `tests/services/setup.service.test.ts` - 13 service unit tests
+- `tests/routes/setups.test.ts` - 11 route integration tests
+
+## Decisions Made
+- syncSetupItems uses delete-all + re-insert in transaction for simplicity over diff-based sync
+- SQL COALESCE ensures 0 returned for empty setups instead of null
+- removeSetupItem uses raw SQL WHERE clause for compound condition (setupId + itemId)
+
+## Deviations from Plan
+
+None - plan executed exactly as written.
+
+## Issues Encountered
+
+None
+
+## User Setup Required
+
+None - no external service configuration required.
+
+## Next Phase Readiness
+- Setup API complete and tested, ready for frontend consumption in Plan 02
+- Junction table pattern established for any future many-to-many relationships
+
+---
+*Phase: 03-setups-and-dashboard*
+*Completed: 2026-03-15*