refactor(search): remove NLP error codes and application config

Remove SMART_SEARCH_UNAVAILABLE and SMART_SEARCH_RATE_LIMITED error codes
from ErrorCode enum; remove nlp and nl-search configuration blocks from
application.yaml; remove nlp config block from application-dev.yaml.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/src/main/java/org/raddatz/familienarchiv/exception/ErrorCode.java

@@ -135,12 +135,6 @@ public enum ErrorCode {
     /** The merge target is a descendant of the source tag. 400 */
     TAG_MERGE_INVALID_TARGET,
 
-    // --- NL Search ---
-    /** Ollama is unreachable or timed out. 503 */
-    SMART_SEARCH_UNAVAILABLE,
-    /** NL search rate limit exceeded (5 requests per user per minute). 429 */
-    SMART_SEARCH_RATE_LIMITED,
-
     // --- Generic ---
     /** Request validation failed (missing or malformed fields). 400 */
     VALIDATION_ERROR,

backend/src/main/resources/application-dev.yaml

@@ -12,6 +12,3 @@ springdoc:
     enabled: true
     path: /swagger-ui.html
 
-app:
-  nlp:
-    base-url: http://localhost:8001

backend/src/main/resources/application.yaml

@@ -130,13 +130,6 @@ app:
     # The loader maps columns by header name — no positional indices (see ADR-025).
     dir: ${IMPORT_DIR:/import}
 
-  nlp:
-    base-url: http://nlp-service:8001
-
-  nl-search:
-    rate-limit:
-      max-requests-per-minute: 20
-
 ocr:
   sender-model:
     activation-threshold: 100