docs(01-01): complete UPSERT + FK enforcement plan

- Create 01-01-SUMMARY.md documenting both bug fixes and test addition
- Advance plan counter to 2/2 in STATE.md
- Record decisions and metrics in STATE.md
- Update ROADMAP.md plan progress (1/2 summaries)
- Mark requirements DATA-01 and DATA-02 complete

.planning/REQUIREMENTS.md

@@ -9,8 +9,8 @@ Requirements for this milestone. Each maps to roadmap phases.
 
 ### Data Integrity
 
-- [ ] **DATA-01**: Webhook events use proper UPSERT (ON CONFLICT DO UPDATE) instead of INSERT OR REPLACE, preserving tag assignments when an image receives a new event
+- [x] **DATA-01**: Webhook events use proper UPSERT (ON CONFLICT DO UPDATE) instead of INSERT OR REPLACE, preserving tag assignments when an image receives a new event
-- [ ] **DATA-02**: SQLite foreign key enforcement is enabled (PRAGMA foreign_keys = ON) so tag deletion properly cascades to tag assignments
+- [x] **DATA-02**: SQLite foreign key enforcement is enabled (PRAGMA foreign_keys = ON) so tag deletion properly cascades to tag assignments
 - [ ] **DATA-03**: Webhook and API endpoints enforce request body size limits (e.g., 1MB) to prevent OOM from oversized payloads
 - [ ] **DATA-04**: Test error handling uses t.Fatal instead of silent returns, so test failures are never swallowed
 
@@ -91,8 +91,8 @@ Which phases cover which requirements. Updated during roadmap creation.
 
 | Requirement | Phase | Status |
 |-------------|-------|--------|
-| DATA-01 | Phase 1 | Pending |
+| DATA-01 | Phase 1 | Complete |
-| DATA-02 | Phase 1 | Pending |
+| DATA-02 | Phase 1 | Complete |
 | DATA-03 | Phase 1 | Pending |
 | DATA-04 | Phase 1 | Pending |
 | REFAC-01 | Phase 2 | Pending |

.planning/ROADMAP.md

@@ -31,7 +31,7 @@ Decimal phases appear between their surrounding integers in numeric order.
 **Plans**: 2 plans
 
 Plans:
-- [ ] 01-01-PLAN.md — Fix INSERT OR REPLACE → UPSERT in UpdateEvent(); enable PRAGMA foreign_keys = ON in InitDB(); add regression test
+- [x] 01-01-PLAN.md — Fix INSERT OR REPLACE → UPSERT in UpdateEvent(); enable PRAGMA foreign_keys = ON in InitDB(); add regression test
 - [ ] 01-02-PLAN.md — Add http.MaxBytesReader body limits to 3 handlers (413 on oversized); replace 6 silent test returns with t.Fatalf
 
 ### Phase 2: Backend Refactor

.planning/STATE.md

@@ -1,3 +1,17 @@
+---
+gsd_state_version: 1.0
+milestone: v1.0
+milestone_name: milestone
+status: Ready to execute
+stopped_at: Completed 01-01-PLAN.md (UPSERT + FK enforcement)
+last_updated: "2026-03-23T20:16:27.362Z"
+progress:
+  total_phases: 4
+  completed_phases: 0
+  total_plans: 2
+  completed_plans: 1
+---
+
 # Project State
 
 ## Project Reference
@@ -5,20 +19,17 @@
 See: .planning/PROJECT.md (updated 2026-03-23)
 
 **Core value:** Reliable, persistent visibility into which services need updating — data never disappears, and the dashboard is the one place you trust to show the full picture.
-**Current focus:** Phase 1 — Data Integrity
+**Current focus:** Phase 01 — data-integrity
 
 ## Current Position
 
-Phase: 1 of 4 (Data Integrity)
+Phase: 01 (data-integrity) — EXECUTING
-Plan: 0 of ? in current phase
+Plan: 2 of 2
-Status: Ready to plan
-Last activity: 2026-03-23 — Roadmap created; ready to begin Phase 1 planning
-
-Progress: [░░░░░░░░░░] 0%
 
 ## Performance Metrics
 
 **Velocity:**
+
 - Total plans completed: 0
 - Average duration: —
 - Total execution time: —
@@ -30,10 +41,12 @@ Progress: [░░░░░░░░░░] 0%
 | - | - | - | - |
 
 **Recent Trend:**
+
 - Last 5 plans: —
 - Trend: —
 
 *Updated after each plan completion*
+| Phase 01 P01 | 2 | 2 tasks | 2 files |
 
 ## Accumulated Context
 
@@ -46,6 +59,8 @@ Recent decisions affecting current work:
 - Backend refactor must be behavior-neutral — all existing tests must pass before PostgreSQL is introduced
 - No ORM or query builder — raw SQL per store implementation; 8 operations across 3 tables is too small to justify a dependency
 - `DATABASE_URL` present activates PostgreSQL; absent falls back to SQLite with `DB_PATH` — no separate `DB_DRIVER` variable
+- [Phase 01]: Use named-column UPSERT (ON CONFLICT DO UPDATE) to preserve tag_assignments child rows on re-insert
+- [Phase 01]: Enable PRAGMA foreign_keys = ON in InitDB() before DDL to activate ON DELETE CASCADE for tag deletion
 
 ### Pending Todos
 
@@ -58,6 +73,6 @@ None yet.
 
 ## Session Continuity
 
-Last session: 2026-03-23
+Last session: 2026-03-23T20:16:27.360Z
-Stopped at: Roadmap created; STATE.md initialized
+Stopped at: Completed 01-01-PLAN.md (UPSERT + FK enforcement)
 Resume file: None

.planning/phases/01-data-integrity/01-01-SUMMARY.md

@@ -0,0 +1,81 @@
+---
+phase: 01-data-integrity
+plan: "01"
+subsystem: backend/storage
+tags: [sqlite, bug-fix, data-integrity, upsert, foreign-keys]
+dependency_graph:
+  requires: []
+  provides: [DATA-01, DATA-02]
+  affects: [pkg/diunwebhook/diunwebhook.go]
+tech_stack:
+  added: []
+  patterns: [SQLite UPSERT (ON CONFLICT DO UPDATE), PRAGMA foreign_keys = ON]
+key_files:
+  created: []
+  modified:
+    - pkg/diunwebhook/diunwebhook.go
+    - pkg/diunwebhook/diunwebhook_test.go
+decisions:
+  - "Use named-column INSERT with ON CONFLICT(image) DO UPDATE SET (UPSERT) instead of INSERT OR REPLACE to preserve tag_assignments child rows"
+  - "Enable PRAGMA foreign_keys = ON immediately after SetMaxOpenConns(1) so all connections (single-connection pool) enforce FK constraints"
+metrics:
+  duration: "2 minutes"
+  completed_date: "2026-03-23"
+  tasks_completed: 2
+  files_modified: 2
+---
+
+# Phase 01 Plan 01: Fix SQLite Data-Destruction Bugs (UPSERT + FK Enforcement) Summary
+
+**One-liner:** SQLite UPSERT replaces INSERT OR REPLACE to preserve tag_assignments on re-insert, and PRAGMA foreign_keys = ON enables ON DELETE CASCADE for tag deletion.
+
+## What Was Built
+
+Fixed two silent data-destruction bugs in the SQLite persistence layer:
+
+**Bug DATA-01 (INSERT OR REPLACE destroying tags):** SQLite's `INSERT OR REPLACE` is implemented as DELETE + INSERT. The DELETE fired `ON DELETE CASCADE` on `tag_assignments.image`, silently removing the tag assignment every time a new DIUN event arrived for an already-tagged image. Fixed by replacing the statement with a proper UPSERT (`INSERT INTO ... ON CONFLICT(image) DO UPDATE SET`) that only updates the non-key columns, leaving `tag_assignments` untouched.
+
+**Bug DATA-02 (FK enforcement disabled):** SQLite disables foreign key enforcement by default. `PRAGMA foreign_keys = ON` was never executed, so `ON DELETE CASCADE` on `tag_assignments.tag_id` did not fire when a tag was deleted. Fixed by executing the pragma immediately after `db.SetMaxOpenConns(1)` in `InitDB()`, before any DDL statements.
+
+## Tasks Completed
+
+| Task | Name | Commit | Files |
+|------|------|--------|-------|
+| 1 | Replace INSERT OR REPLACE with UPSERT + add PRAGMA FK enforcement | 7edbaad | pkg/diunwebhook/diunwebhook.go |
+| 2 | Add regression test TestUpdateEvent_PreservesTagOnUpsert | e2d388c | pkg/diunwebhook/diunwebhook_test.go |
+
+## Decisions Made
+
+1. **Named-column UPSERT over positional INSERT OR REPLACE:** The UPSERT explicitly lists 15 columns and their `excluded.*` counterparts in the DO UPDATE SET clause, making column mapping unambiguous and safe for future schema additions.
+
+2. **acknowledged_at hardcoded NULL in UPSERT:** The UPSERT sets `acknowledged_at = NULL` unconditionally in both the INSERT and the ON CONFLICT update clause. This ensures a new event always resets the acknowledged state, matching the pre-existing behavior and test expectations.
+
+3. **PRAGMA placement before DDL:** The FK pragma is placed before all CREATE TABLE statements to ensure the enforcement is active when foreign key relationships are first defined, not just at query time.
+
+## Deviations from Plan
+
+None — plan executed exactly as written.
+
+## Verification Results
+
+- `grep -c "INSERT OR REPLACE INTO updates" pkg/diunwebhook/diunwebhook.go` → `0` (confirmed)
+- `grep -c "PRAGMA foreign_keys = ON" pkg/diunwebhook/diunwebhook.go` → `1` (confirmed)
+- `grep -c "ON CONFLICT(image) DO UPDATE SET" pkg/diunwebhook/diunwebhook.go` → `1` (confirmed)
+- Full test suite: 29 tests pass, 0 failures, coverage 63.6%
+- `TestDismissHandler_ReappearsAfterNewWebhook` — PASS
+- `TestDeleteTagHandler_CascadesAssignment` — PASS
+- `TestUpdateEvent_PreservesTagOnUpsert` — PASS (new regression test)
+
+## Known Stubs
+
+None.
+
+## Self-Check: PASSED
+
+Files exist:
+- FOUND: pkg/diunwebhook/diunwebhook.go (modified)
+- FOUND: pkg/diunwebhook/diunwebhook_test.go (modified, contains TestUpdateEvent_PreservesTagOnUpsert)
+
+Commits exist:
+- FOUND: 7edbaad — fix(01-01): replace INSERT OR REPLACE with UPSERT and enable FK enforcement
+- FOUND: e2d388c — test(01-01): add TestUpdateEvent_PreservesTagOnUpsert regression test