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/precedent_library.py

@@ -257,8 +257,11 @@ async def reextract_halachot(
         case_law_id = UUID(case_law_id)
 
     record = await db.get_case_law(case_law_id)
-    if not record or record.get("source_kind") != "external_upload":
-        raise ValueError("precedent not found or not chair-uploaded")
+    if not record:
+        raise ValueError("precedent not found")
+    # Was restricted to source_kind='external_upload'; opened 2026-05-06 so
+    # internal_committee rows can also be re-extracted when ingest produced
+    # bad data. See note in db.request_metadata_extraction.
 
     await progress("extracting_halachot", 50, "מחלץ הלכות מחדש")
     result = await halacha_extractor.extract(case_law_id)
@@ -402,8 +405,9 @@ async def reextract_metadata(
         case_law_id = UUID(case_law_id)
 
     record = await db.get_case_law(case_law_id)
-    if not record or record.get("source_kind") != "external_upload":
-        raise ValueError("precedent not found or not chair-uploaded")
+    if not record:
+        raise ValueError("precedent not found")
+    # See note in db.request_metadata_extraction — opened to all source kinds.
 
     await progress("extracting_metadata", 40, "מחלץ מטא-דאטה (תקציר, תגיות)")
     result = await precedent_metadata_extractor.extract_and_apply(case_law_id)