fix(precedent-library): allow re-extraction for internal_committee rows

The "חלץ מטא-דאטה" / "חלץ הלכות" buttons in the UI were returning 404
for any precedent with `source_kind != 'external_upload'`. The original
restriction was meant to keep LLM extraction off internal-committee
imports (their metadata supposedly came from the case file system),
but the same precedent rows can still need re-extraction when ingest
produces broken data — e.g. the corrupted `subject_tags` value
`['[','"','ה','י',...]` that motivated this change (an early ingest
stored a JSON literal into a TEXT[] column, which Postgres split into
single chars).

Two changes here:

1. db.request_metadata_extraction / request_halacha_extraction:
   drop the `AND source_kind='external_upload'` filter. The extractor
   already preserves user values (only fills empty fields), so this
   is safe.

2. precedent_metadata_extractor.extract_and_apply: detect the
   character-by-character corruption above and treat it as empty so
   the freshly-extracted tags actually replace the broken ones.
   Heuristic: 3+ elements where every element is at most 2 chars
   (legitimate tags are multi-character Hebrew words).

Coolify deploy required for the FastAPI container to pick this up.

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

@@ -1915,7 +1915,7 @@ async def update_case_law(case_law_id: UUID, **fields) -> dict | None:
     precedent_level, is_binding.
     """
     allowed = {
-        "case_name", "court", "date", "practice_area", "appeal_subtype",
+        "case_number", "case_name", "court", "date", "practice_area", "appeal_subtype",
         "subject_tags", "summary", "headnote", "key_quote", "source_url",
         "source_type", "precedent_level", "is_binding",
     }
@@ -2466,22 +2466,31 @@ async def precedent_library_stats() -> dict:
 
 async def request_metadata_extraction(case_law_id: UUID) -> bool:
     """Stamp ``metadata_extraction_requested_at`` for the local MCP worker
-    to pick up. Returns False if the row is missing."""
+    to pick up. Returns False if the row is missing.
+
+    Originally restricted to ``source_kind='external_upload'`` (see git
+    blame). Opened to all source kinds 2026-05-06 — internal_committee
+    rows can also need re-extraction (e.g. corrupted subject_tags from
+    an early ingest pipeline). The extractor itself preserves user
+    values (``precedent_metadata_extractor.extract_and_apply`` only
+    fills empty fields), so this is safe.
+    """
     pool = await get_pool()
     result = await pool.execute(
         "UPDATE case_law SET metadata_extraction_requested_at = now() "
-        "WHERE id = $1 AND source_kind = 'external_upload'",
+        "WHERE id = $1",
         case_law_id,
     )
     return result == "UPDATE 1"
 
 
 async def request_halacha_extraction(case_law_id: UUID) -> bool:
-    """Same but for halacha extraction."""
+    """Same but for halacha extraction. See note on
+    :func:`request_metadata_extraction` re: opening to all source kinds."""
     pool = await get_pool()
     result = await pool.execute(
         "UPDATE case_law SET halacha_extraction_requested_at = now() "
-        "WHERE id = $1 AND source_kind = 'external_upload'",
+        "WHERE id = $1",
         case_law_id,
     )
     return result == "UPDATE 1"