feat(ingest): recompute searchable on ingest + metadata completion (GAP-13, FU-2a)

Wire db.recompute_searchable into the ingest pipeline (after statuses are set) and into
extract_and_apply (after fields are persisted to DB, success path only).

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

mcp-server/src/legal_mcp/services/precedent_metadata_extractor.py

@@ -368,6 +368,8 @@ async def extract_and_apply(
     if not suggested:
         return {"status": "no_metadata", "fields": []}
     result = await apply_to_record(case_law_id, suggested, overwrite_case_number=overwrite_case_number)
+    if result["updated"]:
+        await db.recompute_searchable(case_law_id)
     return {
         "status": "completed" if result["updated"] else "no_changes",
         "fields": result["fields"],