Refactor all list APIs for server-side pagination, search, and sort

All list endpoints now return paginated responses:
  { data: [...], pagination: { page, limit, total, totalPages } }

Query params: ?page=1&limit=25&q=search&sort=name&order=asc

Changes:
- Added PaginationSchema in @forte/shared for consistent param parsing
- Added pagination utils (withPagination, withSort, buildSearchCondition,
  paginatedResponse) in backend
- Refactored all services: AccountService, MemberService, CategoryService,
  SupplierService, ProductService, InventoryUnitService
- Merged separate /search endpoints into list endpoints via ?q= param
- Removed AccountSearchSchema and ProductSearchSchema (replaced by
  PaginationSchema)
- Added pagination test (5 items, page 1 limit 2, expect totalPages=3)
- Updated CLAUDE.md with API conventions
- 34 tests passing

CLAUDE.md

@@ -39,6 +39,16 @@
 - `bun run lint` — lint all packages
 - `bun run format` — format all files with Prettier
 
+## API Conventions
+- All list endpoints support server-side pagination, search, and sorting via query params:
+  - `?page=1&limit=25` — pagination (default: page 1, 25 per page, max 100)
+  - `?q=search+term` — full-text search across relevant columns
+  - `?sort=name&order=asc` — sorting by field name, asc or desc
+- List responses always return `{ data: [...], pagination: { page, limit, total, totalPages } }`
+- Search and filtering is ALWAYS server-side, never client-side
+- Use `PaginationSchema` from `@forte/shared/schemas` to parse query params
+- Use pagination helpers from `packages/backend/src/utils/pagination.ts`
+
 ## Conventions
 - Shared Zod schemas are the single source of truth for validation (used on both frontend and backend)
 - Business logic lives in `@forte/shared`, not in individual app packages