Thanks for asking me to work on this. I will get started on it and keep this PR's description up to date as I form a plan and make progress.

This pull request was created as a result of the following prompt from Copilot chat.

Add a new enterprise (multi-tenant) feature to support path-isolated tenancy, enterprise management, employee sync via API, admin audit/review workflow, and frontend enterprise UI pieces. Do not change existing tables; add new Prisma models and migrations. Implement server modules, middleware, admin endpoints, and frontend components, and include environment variable controls.

Requirements (implement exactly):

1. Prisma schema and migration

• Append new Prisma models in prisma/schema.prisma: Enterprise, EnterpriseDomain, EnterpriseMember, EnterpriseTeam, Employee, enums EnterpriseStatus and EnterpriseRole. Keep relations to existing User model. Do not modify existing models.
• Add a SQL migration file prisma/migrations/20251019_add_enterprise_tables.sql that creates corresponding tables and foreign keys where safe.

2. Environment variables

• Add .env.example.enterprise listing:
  • ENTERPRISE_ENABLED
  • ENTERPRISE_CHARGE_REQUIRED
  • ENTERPRISE_SAAS_MODE
  • ENTERPRISE_ADMIN_API_KEY
  • ENTERPRISE_EXTERNAL_SYNC_KEY

3. Server: new module packages/server/src/modules/enterprise

• Add enterprise.service.ts implementing: createEnterprise (creates PENDING enterprise, member for creator), approveEnterprise, rejectEnterprise, getBySlug, listUserEnterprises, addEmployeeAndUser (creates Employee and calls existing auth service to create user if missing), syncEmployeesFromExternal.
• Add enterprise.controller.ts registering Express routes consistent with repository with endpoints:
  • POST /api/enterprises (requireAuth) -> create (PENDING)
  • GET /api/enterprises/me (requireAuth) -> list user's active enterprises
  • GET /api/enterprises/slug/:slug -> get by slug
  • POST /api/enterprises/:enterpriseId/employees/sync -> validateApiKey(ENTERPRISE_EXTERNAL_SYNC_KEY) -> sync
• Ensure imports and registrations consistent with repo (if routes are registered via server bootstrap, add note to register route at server entrypoint).

4. Middleware

• Add tenant middleware packages/server/src/middleware/tenant.middleware.ts: path-based tenant resolver (/e/:slug/*), host domain mapping, attach req.enterprise and rewrite req.url to remove prefix.
• Add packages/server/src/middleware/apikey.ts and adminAuth.ts for API key validation.

5. Admin module

• Add admin-enterprise.controller.ts under packages/server/src/modules/admin to allow admin operations:
  • GET /api/admin/enterprises -> list all enterprises (protected by ENTERPRISE_ADMIN_API_KEY)
  • POST /api/admin/enterprises/:enterpriseId/approve
  • POST /api/admin/enterprises/:enterpriseId/reject

6. Frontend

• Add components packages/web/src/components/EnterpriseSwitcher.tsx and EnterpriseCreateForm.tsx implementing listing /api/enterprises/me and posting /api/enterprises.

7. Routing and path isolation guidance

• Add middleware usage in server bootstrap: use tenantResolver before main app routes; document how to prefix routes with /e/:slug and how to rewrite URL in middleware.

8. Tests / docs

• Add docs/enterprise.md describing feature flags, env vars, migration steps, admin workflow, domain verification, OAuth2 notes, and external sync API contract.

Implementation notes for developer:

• Reuse existing auth service API: authService.createUserIfNotExists({ email, firstName, lastName }) — if actual method differs, adapt accordingly.
• Use PrismaClient from @prisma/client.
• Protect admin endpoints with X-Enterprise-Admin-Key header checked against ENTERPRISE_ADMIN_API_KEY.
• Protect external sync with X-Enterprise-API-Key header checked against ENTERPRISE_EXTERNAL_SYNC_KEY.
• Do not modify existing tables; create new tables and use string references to existing Team ids where appropriate (EnterpriseTeam.teamId).
• Add file comments where further integration points are needed (route registration, auth service import path adaptations).

Files to create (provide each file contents):

• prisma/schema.prisma (append new models)
• prisma/migrations/20251019_add_enterprise_tables.sql
• .env.example.enterprise
• packages/server/src/modules/enterprise/enterprise.service.ts
• packages/server/src/modules/enterprise/enterprise.controller.ts
• packages/server/src/modules/admin/admin-enterprise.controller.ts
• packages/server/src/middleware/tenant.middleware.ts
• packages/server/src/middleware/apikey.ts
• packages/server/src/middleware/adminAuth.ts
• packages/web/src/components/EnterpriseSwitcher.tsx
• packages/web/src/components/EnterpriseCreateForm.tsx
• docs/enterprise.md

Make sure code compiles under TypeScript; add // TODO comments where integration to existing codebase is required (e.g., importing existing authService, registering routes in server bootstrap). Keep code style consistent with TypeScript, using async/await and express Request/Response types. Return appropriate status codes and JSON responses.

Create a new branch feat/enterprise-multitenant off main, add these files with the contents prepared in earlier messages, and open a PR targeting main. Include a clear PR description summarizing changes and migration instructions. Do not open any issues.

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