refactor(search): remove NLP/smart-search feature entirely (#772)

## Summary

- Removes the NLP/smart-search feature completely — the feature was too unreliable and slow; users get better results with the regular search filters
- Deletes the entire backend `search/` package (NlSearchController, NlQueryParserService, NlpClient, NlSearchRateLimiter — 14 classes + 6 test classes)
- Deletes the `nlp-service/` Python microservice (FastAPI, rapidfuzz, DB-backed person matching)
- Removes all frontend NL search components: SmartModeToggle, SmartSearchStatus, InterpretationChipRow, DisambiguationPicker, chip-types, theme-chip-removal
- Strips smart-mode logic from SearchFilterBar and documents/+page.svelte
- Removes `SMART_SEARCH_UNAVAILABLE` / `SMART_SEARCH_RATE_LIMITED` error codes from backend, frontend types, and all three i18n files (de/en/es)
- Removes `nlp-service` container and `APP_NLP_BASE_URL` from both docker-compose files
- Removes Ollama/NLP Prometheus scrape job and Grafana dashboard
- Deletes ADRs 028 (×2), 034, 035

## Test plan

- [ ] Backend compiles: `cd backend && ./mvnw compile -q` → BUILD SUCCESS
- [ ] Frontend server tests pass: `cd frontend && npm run test -- --project=server`
- [ ] No NLP/smart-search references remain in source: `grep -r "SmartSearch\|NlSearch\|nlp-service\|SMART_SEARCH" backend/src frontend/src`
- [ ] `docker compose config` validates both compose files
- [ ] Search page loads, filter bar works, no smart-mode toggle visible

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Marcel <marcel@familienarchiv>
Reviewed-on: #772

frontend/src/lib/shared/errors.ts

@@ -53,8 +53,6 @@ export type ErrorCode =
 	| 'FORBIDDEN'
 	| 'CSRF_TOKEN_MISSING'
 	| 'TOO_MANY_LOGIN_ATTEMPTS'
-	| 'SMART_SEARCH_UNAVAILABLE'
-	| 'SMART_SEARCH_RATE_LIMITED'
 	| 'VALIDATION_ERROR'
 	| 'BATCH_TOO_LARGE'
 	| 'BULK_EDIT_TOO_MANY_IDS'
@@ -180,10 +178,6 @@ export function getErrorMessage(code: ErrorCode | string | undefined): string {
 			return m.error_csrf_token_missing();
 		case 'TOO_MANY_LOGIN_ATTEMPTS':
 			return m.error_too_many_login_attempts();
-		case 'SMART_SEARCH_UNAVAILABLE':
-			return m.error_smart_search_unavailable();
-		case 'SMART_SEARCH_RATE_LIMITED':
-			return m.error_smart_search_rate_limited();
 		case 'VALIDATION_ERROR':
 			return m.error_validation_error();
 		case 'BATCH_TOO_LARGE':