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/ROADMAP.md

@@ -120,7 +120,7 @@ Plans:
   1. A user can save a one-off expense category (with an icon) to their quick-add library from the budget item add flow
   2. When adding a one-off item, the user can browse their quick-add library and select a saved category — the item populates with that category and icon
   3. The quick-add library management page lets the user add, edit, and remove saved categories
-**Plans:** 2 plans
+**Plans:** 1/2 plans executed
 
 Plans:
 - [ ] 07-01-PLAN.md — DB migration, QuickAddItem model, CRUD queries, REST handlers at /api/quick-add
@@ -154,5 +154,5 @@ Phases execute in numeric order: 1 -> 2 -> 3 -> 4 -> 5 -> 6 -> 7 -> 8
 | 4. Chart Polish and Bug Fixes | v1.0 | 2/2 | Complete | 2026-03-12 |
 | 5. Template Data Model and API | v1.1 | 2/2 | Complete | 2026-03-12 |
 | 6. Template Frontend and Workflow Replacement | v1.1 | 2/2 | Complete | 2026-03-12 |
-| 7. Quick-Add Library | v1.1 | 0/2 | Not started | - |
+| 7. Quick-Add Library | 1/2 | In Progress|  | - |
 | 8. Layout and Density Rethink | v1.1 | 0/2 | Not started | - |