1## 1. Data model23- [x] 1.1 Add `users` table with unique lower(email) index (migration 0031)4- [x] 1.2 Add `sessions` table keyed by random 32-byte id (migration 0032)5- [x] 1.3 Add `failed_logins` counter and `locked_until` to `users` (migration 0033)67## 2. Authentication89- [x] 2.1 Implement argon2id hashing helpers in `internal/auth/password.go`10- [x] 2.2 Implement login/logout handlers and session cookie11- [x] 2.3 Replace shared-token middleware with session middleware12- [x] 2.4 Implement lockout after 5 failed attempts1314## 3. UI and cleanup1516- [x] 3.1 Add login page with "Remember me" checkbox17- [x] 3.2 Add nightly job to purge expired sessions18- [x] 3.3 Remove shared team token from config and docs