docs(06-03): complete useFirstRunState hook and DB schema push summary

- SUMMARY.md for plan 06-03 with all task results
- STATE.md updated: Phase 06 complete (3/3 plans)
- ROADMAP.md updated: Phase 06 marked complete

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.planning/phases/06-preset-data-first-run-detection-and-db-safety/06-03-SUMMARY.md

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+---
+phase: 06
+plan: 03
+subsystem: first-run-detection
+tags: [hooks, supabase, migrations, first-run]
+started: "2026-04-20T17:32:09Z"
+completed: "2026-04-20T18:07:20Z"
+status: complete
+dependency_graph:
+  requires: [06-01, 06-02]
+  provides: [useFirstRunState-hook, db-schema-live]
+  affects: [phase-07-wizard]
+tech_stack:
+  added: []
+  patterns: [derived-state-hook, loading-guard-pattern]
+key_files:
+  created:
+    - src/hooks/useFirstRunState.ts
+  modified: []
+decisions:
+  - "Hook derives state from existing React Query caches (useCategories + useTemplate) with zero additional network calls"
+  - "DB migrations applied manually by user via supabase db push after checkpoint gate"
+metrics:
+  duration: ~35min (including checkpoint wait)
+  tasks_completed: 3
+  files_created: 1
+  files_modified: 0
+---
+
+# Phase 06 Plan 03: useFirstRunState Hook and DB Schema Push Summary
+
+Derived first-run detection hook reading from React Query cache with loading guard to prevent spurious redirects, plus live DB schema with uniqueness constraints and setup_completed column.
+
+## What Was Built
+
+### useFirstRunState Hook (src/hooks/useFirstRunState.ts)
+
+A read-only derived state hook that composes `useCategories()` and `useTemplate()` to determine whether the current user is a first-run user (no categories or no template items). Returns `{ isFirstRun: boolean, loading: boolean }`. The `loading` flag is critical -- callers in Phase 7 must check `!loading && isFirstRun` before redirecting to prevent false positives while queries are in flight.
+
+### DB Schema Push (migrations 006 + 007)
+
+User applied both migrations via `supabase db push`:
+- Migration 006: UNIQUE constraints on `budgets(user_id, start_date)` and `categories(user_id, name)` with safe deduplication
+- Migration 007: `setup_completed` boolean column on `profiles` with backfill for existing users
+
+## Task Execution
+
+| Task | Name | Commit | Status |
+|------|------|--------|--------|
+| 1 | Create useFirstRunState.ts | 0c1105f | Complete |
+| 2 | DB schema push (migrations 006+007) | Manual (user) | Complete - user applied |
+| 3 | Human verification checkpoint | N/A | Approved by user |
+
+## Decisions Made
+
+1. **Zero-network-call design** -- Hook reads from existing React Query caches rather than making its own Supabase calls, avoiding redundant fetches.
+2. **Manual DB push** -- `supabase db push` required interactive confirmation; user ran it manually after checkpoint gate.
+
+## Deviations from Plan
+
+None -- plan executed exactly as written.
+
+## Known Stubs
+
+None -- hook is fully wired to existing data sources.
+
+## Verification Results
+
+- `export function useFirstRunState` found in hook file
+- Both `useCategories` and `useTemplate` imports present
+- `npx tsc --noEmit` passes with zero errors
+- Migration files 006 and 007 exist in supabase/migrations/
+- User confirmed DB constraints and setup_completed column are live in Supabase dashboard
+
+## Requirements Covered
+
+- **AUTO-01**: useFirstRunState provides first-run detection for auto-budget flow
+- **AUTO-03**: No hardcoded currency -- amounts are plain numbers throughout
+- **SETUP-01**: setup_completed column + backfill (plan 01) + useFirstRunState detection (plan 03)
+- **SETUP-02**: Preset library with 19 items delivered in plan 02
+
+## Self-Check: PASSED
+
+- [x] src/hooks/useFirstRunState.ts exists
+- [x] Commit 0c1105f verified in git log
+- [x] TypeScript compiles cleanly
+- [x] Migration files present on disk