- Add ListQuickAddItems, CreateQuickAddItem, UpdateQuickAddItem, DeleteQuickAddItem handler methods
- Register GET/POST /api/quick-add and PUT/DELETE /api/quick-add/{itemId} in authenticated route group
- Validate name non-empty on create and update; return 404 on update when item not found
- Create 003_quick_add_library.sql with quick_add_items table and user index
- Add QuickAddItem struct to models.go following Category pattern
- Add ListQuickAddItems, CreateQuickAddItem, UpdateQuickAddItem, DeleteQuickAddItem to queries.go
- Add /api/template route group: GET, PUT /, POST/PUT/DELETE items, PUT items/reorder
- Add POST /api/budgets/generate before /{id} routes to avoid chi treating 'generate' as an id param
- /items/reorder registered before /items/{itemId} for correct static-before-param routing
- Create 002_templates.sql: item_tier enum, ALTER budget_items, templates and template_items tables with CHECK constraint
- Add ItemTier type with fixed/variable/one_off constants to models.go
- Add ItemTier field to BudgetItem struct
- Add Template, TemplateItem, TemplateDetail structs