feat(proceeding-type): explicit ערר/בל"מ field for cases + corpus

Same case_number can exist as both a regular appeal (ערר) and an
extension-of-time request (בל"מ), and we were inferring the difference
from appeal_subtype prefixes — fragile, and case-number lookups
weren't disambiguated. Now stored as a first-class field on both
case_law (corpus) and cases (live cases), with partial unique indexes
on (case_number, proceeding_type).

- SCHEMA_V15: column + CHECK constraints + backfill from
  appeal_subtype LIKE 'extension_request_%' + partial unique indexes
  replace the old global UNIQUE(case_number).
- derive_proceeding_type() centralizes the inference rule
  (extension_request_* → בל"מ; subject regex fallback; default ערר).
- Metadata extractor prompt asks Claude to populate the new field
  explicitly; apply_to_record writes it for internal_committee rows.
- internal_decision_upload, case_create, case_update accept an
  optional proceeding_type; FastAPI request models expose it.
- Wizard + edit dialog get a sided Select; case header renders the
  resolved label (ערר / בל"מ).
- Uploaded the 2 staged בל"מ decisions on betterment levy:
  8126/24 (סופר נוח, 13 chunks), 8047/23 (הרנון, 48 chunks).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

mcp-server/src/legal_mcp/tools/internal_decisions.py

@@ -21,6 +21,10 @@ from legal_mcp.services import internal_decisions as int_svc
 # Valid Hebrew district names (matches _COURT_TO_DISTRICT in service)
 VALID_DISTRICTS = {"ירושלים", "מרכז", "תל אביב", "תל-אביב", "צפון", "דרום", "חיפה", "ארצי"}
 
+# proceeding_type — ערר vs בל"מ. The service can derive it from
+# appeal_subtype/subject if left empty, so this stays optional at the API.
+VALID_PROCEEDING_TYPES = {"ערר", 'בל"מ'}
+
 
 def _ok(payload) -> str:
     return json.dumps(payload, ensure_ascii=False, indent=2, default=str)
@@ -43,6 +47,7 @@ async def internal_decision_upload(
     subject_tags: list[str] | None = None,
     summary: str = "",
     is_binding: bool = False,
+    proceeding_type: str = "",
 ) -> str:
     """העלאת החלטה של ועדת ערר (internal_committee) לקורפוס הסמכותי.
 
@@ -62,6 +67,7 @@ async def internal_decision_upload(
         appeal_subtype: building_permit / וכו'.
         subject_tags: תגיות נושא.
         is_binding: בד"כ False (ועדת ערר לא מחייבת ועדה אחרת — שכנוע אופקי).
+        proceeding_type: 'ערר' או 'בל"מ'. אם ריק — נגזר מ-appeal_subtype/case_name.
 
     Returns: JSON עם case_law_id, מספר chunks, halachot_pending.
     """
@@ -83,6 +89,11 @@ async def internal_decision_upload(
             f"district לא תקין: {district!r}. ערכים תקפים: "
             + ", ".join(sorted(VALID_DISTRICTS))
         )
+    if proceeding_type.strip() and proceeding_type.strip() not in VALID_PROCEEDING_TYPES:
+        return _err(
+            f"proceeding_type לא תקין: {proceeding_type!r}. ערכים תקפים: "
+            + ", ".join(sorted(VALID_PROCEEDING_TYPES))
+        )
 
     try:
         result = await int_svc.ingest_internal_decision(
@@ -98,6 +109,7 @@ async def internal_decision_upload(
             summary=summary,
             is_binding=is_binding,
             file_path=file_path,
+            proceeding_type=proceeding_type,
         )
     except Exception as e:
         return _err(str(e))