[A1] Seed default farm/house/user + startup migrate + flock CRUD #5

Sprint A · Foundation · status:partial

The Flock aggregate exists but has no CRUD endpoints, there is no seeded farm/house/user, and migrations are not applied on startup. MVP runs single-farm — seed one default farm + house + admin user so the app (and the SPA login, #20) works end-to-end against a fresh database.

Scope

• Apply EF migrations on startup (or a documented dotnet ef database update bootstrap step).
• Seed one default Account + Farm + House (stable ids, tied to the default tenant).
• Seed a default admin ApplicationUser with known credentials (config-driven email/password; never a hardcoded prod secret — read from config/env, dev default documented). This is what [F0] Scaffold React/Vite SPA + auth + API client shell #20 logs in with.
• Flock CRUD endpoints: create, list, get, deplete.
• Wire tenant stamp (already built) so seeded rows carry the default account id.

Out of scope: farm/house CRUD UI, multi-farm switching, self-service user registration (Phase 1.1).

Done when: against a fresh DB, startup applies migrations + seeds the default farm/house/admin user; the admin can log in via POST /api/v1/auth/login; a flock can be created against the seeded farm/house and listed back.

Migrated from Gitea issue #5 (https://gitea.mforcelabs.com/mforce/cluckwork/issues/5).