feat: consolidate frontend API layer, add query-client, and harden backend Fase 1

Frontend:
- Consolidate duplicate API layers into single src/lib/axios.ts per app
- Remove src/lib/api-client.ts and src/utils/api.ts (admin)
- Add src/lib/query-client.ts with TanStack Query config per app
- Update all imports and auto-import config

Backend:
- Fix organisations.billing_status default to 'trial'
- Fix user_invitations.invited_by_user_id to nullOnDelete
- Add MeResource with separated app_roles and pivot-based org roles
- Add cross-org check to EventPolicy view() and update()
- Restrict EventPolicy create/update to org_admin/event_manager (not org_member)
- Attach creator as org_admin on organisation store
- Add query scopes to Event and UserInvitation models
- Improve factories with Dutch test data
- Expand test suite from 29 to 41 tests (90 assertions)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

README.md

@@ -131,7 +131,7 @@ make db-shell
 
 | Resource | Contents |
 |----------|----------|
-| [resources/design/](resources/design/) | **Canonical product specs** — place design documents here (often Word). Referenced by `.cursor` as source of truth for features and data model. Expected names include `Crewli_Design_Document_v1.3.docx`, `Crewli_Dev_Guide_v1.0.docx`, `Crewli_Start_Guide_v1.0.docx` (adjust versions if you update files). |
+| [resources/design/](resources/design/) | **Canonical product specs** in Markdown. Referenced by `.cursor` and `CLAUDE.md` as source of truth for features and data model: `design-document.md`, `dev-guide.md`, `start-guide.md`. |
 | [.cursor/ARCHITECTURE.md](.cursor/ARCHITECTURE.md) | System diagram, apps, multi-tenancy, roles, event lifecycle, API route map, core schema overview (summarises `resources/design` when present) |
 | [.cursor/instructions.md](.cursor/instructions.md) | Quick reference, phased roadmap, module build order |
 | [.cursor/rules/](.cursor/rules/) | Workspace, Laravel, Vue, testing conventions |