docs(07-01): complete quick-add library backend plan

- Add 07-01-SUMMARY.md documenting migration, model, queries, and handlers
- Update STATE.md: progress 94%, decisions, session record
- Update ROADMAP.md: phase 7 in-progress with 1/2 plans complete
- Mark requirements QADD-01 and QADD-03 complete

.planning/STATE.md

@@ -3,14 +3,14 @@ gsd_state_version: 1.0
 milestone: v1.1
 milestone_name: Usability and Templates
 status: planning
-stopped_at: Completed 06-template-frontend-and-workflow-replacement-02-PLAN.md
-last_updated: "2026-03-12T12:13:58.556Z"
+stopped_at: Completed 07-quick-add-library-01-PLAN.md
+last_updated: "2026-03-12T12:35:38.859Z"
 last_activity: 2026-03-12 — v1.1 roadmap created, Phases 5-8 defined
 progress:
   total_phases: 8
   completed_phases: 6
-  total_plans: 14
-  completed_plans: 14
+  total_plans: 16
+  completed_plans: 15
   percent: 0
 ---
 
@@ -54,6 +54,7 @@ Progress: [░░░░░░░░░░] 0%
 | Phase 05-template-data-model-and-api P02 | 1min | 2 tasks | 2 files |
 | Phase 06-template-frontend-and-workflow-replacement P01 | 2min | 2 tasks | 7 files |
 | Phase 06-template-frontend-and-workflow-replacement P02 | 2min | 2 tasks | 9 files |
+| Phase 07-quick-add-library P01 | 1min | 2 tasks | 5 files |
 
 ## Accumulated Context
 
@@ -76,6 +77,9 @@ Recent decisions affecting current work:
 - [Phase 06-template-frontend-and-workflow-replacement]: Reorder swaps sort_order values between adjacent items and sends full updated list to PUT /template/items/reorder
 - [Phase 06-template-frontend-and-workflow-replacement]: 409 conflict on budget generate handled silently — call onCreated() so existing budget becomes selectable
 - [Phase 06-template-frontend-and-workflow-replacement]: BudgetSetup existingBudgets prop retained in signature for interface compatibility but unused after copy-from removal
+- [Phase 07-quick-add-library]: sort_order auto-incremented via subquery at INSERT time so client doesn't need to track current max
+- [Phase 07-quick-add-library]: ListQuickAddItems initializes empty slice (not nil) so API always returns [] not null
+- [Phase 07-quick-add-library]: UpdateQuickAddItem returns 404 via pgx.ErrNoRows check when no row matches id+user_id
 
 ### Pending Todos
 
@@ -88,6 +92,6 @@ None yet.
 
 ## Session Continuity
 
-Last session: 2026-03-12T12:10:58.018Z
-Stopped at: Completed 06-template-frontend-and-workflow-replacement-02-PLAN.md
+Last session: 2026-03-12T12:35:38.858Z
+Stopped at: Completed 07-quick-add-library-01-PLAN.md
 Resume file: None