Add auth bootstrap and database safeguards

AGENTS.md

@@ -33,3 +33,29 @@ Minor alignment fixes, isolated bug fixes, and corrections that do not introduce
 or revise a reusable design decision do not require a documentation update.
 
 If uncertain whether a visual change is significant, update the design system.
+
+## Database preservation
+
+Development data is valuable and may be entered by non-technical contributors.
+Treat embedded database files as persistent user data, not disposable build
+artifacts.
+
+Before deleting, replacing, recreating, renaming, or destructively migrating a
+database—and before any major schema change—create a timestamped JSON backup
+with `npm run db:backup`.
+
+Database work must follow these rules:
+
+1. Confirm which environment and exact database path are in scope.
+2. Stop processes that hold the embedded database lock before backup or restore.
+3. Create and verify a JSON backup before destructive work.
+4. Never overwrite or delete the only available backup.
+5. Keep backups out of Git; they can contain user records and password hashes.
+6. Prefer additive, repeatable schema migrations over database recreation.
+7. After a restore, run the schema migration and verify record counts and
+   critical entities before resuming data entry.
+8. Report the backup path when completing database-destructive work.
+
+Use `npm run db:restore -- <backup-file>` only with an empty, migrated target
+database. The restore script intentionally refuses to merge into a populated
+database.