Update README and moderation commands for localization and migration support

- Revised README to include database migration steps and a new section for database management.
- Enhanced moderation command responses to utilize localized messages for unknown commands.
- Refactored moderation commands to use centralized command data definitions, improving maintainability and consistency.
- Added localization support for command descriptions and options in both German and English.
- Versioned Prisma migrations for better tracking of database changes.

README.md

@@ -19,9 +19,11 @@ Nexumi is a self-hosted public Discord bot with dashboard architecture, built as
    - `pnpm install`
 3. Generate Prisma client:
    - `pnpm prisma:generate`
-4. Start stack:
+4. Apply database migrations:
+   - `pnpm prisma:migrate`
+5. Start stack:
    - `docker compose up -d`
-5. Start bot locally:
+6. Start bot locally:
    - `pnpm --filter @nexumi/bot dev`
 
 ## Verification commands
@@ -30,6 +32,10 @@ Nexumi is a self-hosted public Discord bot with dashboard architecture, built as
 - `pnpm lint`
 - `pnpm test`
 
+## Database
+
+See `docs/DATABASE.md` for migrations, backup and restore runbooks.
+
 ## Backup and restore note
 
 Phase 1 includes the BullMQ foundation for scheduled jobs. Database backup rotation is configured via `BACKUP_RETENTION_DAYS` and the `backups` volume is already reserved in compose.