feat: Stage A finalizers + #35/#36/#37 — critical-gap closure

Four parallel sub-agents closed the remaining critical gaps from the
26/05 Stage A/B sprint. Each block independently tested; aggregated here.

## #30/#31 finalizers (sub-agent A)
* Auto-derive practice_area in case_create from case_number prefix
  (1xxx→rishuy_uvniya, 8xxx→betterment_levy, 9xxx→compensation_197);
  default for CaseCreateRequest is now "" (the DB constraint catches
  any stray "appeals_committee").
* practice_area.py: derive_subtype now handles axis-B domain values
  (rishuy_uvniya/betterment_levy/compensation_197) without parsing the
  case number; new helper derive_domain_practice_area().
* Halacha re-extraction verified unnecessary — all 6 reclassified
  records already had is_binding=false and approved halachot.
* Regression tests: 6 cases in tests/test_corpus_constraints.py
  covering practice_area enum, internal-committee chair/district,
  external-upload arar prefix, MCP guard.
* UI: district input → Select dropdown (7 districts) in
  precedent-edit-sheet.tsx, preserving legacy free-text values.

## #37 בל"מ subtypes (sub-agent B)
* 3 new appeal_subtypes: extension_request_{building_permit,
  betterment_levy,compensation}. APPEALS_COMMITTEE_SUBTYPES extended,
  SUBTYPES_BY_AREA mappings added.
* New helpers: is_blam_subject(), is_blam_subtype(),
  derive_subtype_with_blam(case_number, subject, practice_area).
  case_create now uses it to auto-detect "בקשה להארכת מועד" subjects.
* 3 methodology templates under docs/methodology/extension-request-*.md.
* paperclip_client.py mapping updated for the 3 new subtypes
  (extension_request_building_permit→CMP, the other two→CMPA).
* Frontend: bilingual "בל"מ" badge + filter dropdown on cases list +
  detail header; appeal-type-bars collapseBlam() merges בל"מ into its
  parent domain for aggregate bars.
* Wizard auto-detects בל"מ from subject during case creation.
* 3 Berlinger cases (1017/1018/1019-03-26) migrated to
  appeal_subtype=extension_request_building_permit via psql.

## #35 missing_precedents feature (sub-agent C)
* Schema V13: missing_precedents table (citation, case_id, party,
  legal_topic, status, linked_case_law_id, claim_quote, ...) +
  FK constraints + 3 indexes. Applied via psql + idempotent migration.
* 6 db.py service functions, 3 MCP tools, 6 FastAPI endpoints
  (POST/GET/PATCH/DELETE/upload — upload routes by citation prefix
  to ingest_internal_decision or ingest_precedent).
* Next.js page /missing-precedents with 5 status tabs + filters +
  sidebar badge counter + detail drawer with metadata edit + smart
  upload form that switches fields per committee/court.
* Bootstrap: 7 rows imported from the JSON file
  (3 citations × cases, all status=closed with linked_case_law_id).
* legal-researcher.md: new §2ב.5 with missing_precedent_create
  usage + dedup semantics + tool grant.

## #36 legal_arguments aggregation (sub-agent D)
* Schema V14: legal_arguments + legal_argument_propositions M:M.
  Applied via psql.
* New service argument_aggregator.py with two functions —
  aggregate_claims_to_arguments() (Claude CLI / claude_session) and
  get_legal_arguments(). Graceful llm_unavailable handling when CLI
  is missing (containers).
* 2 MCP tools + 2 API endpoints (POST .../aggregate-arguments as
  BackgroundTask, GET .../legal-arguments).
* Frontend: shadcn Accordion + new legal-arguments-panel.tsx with
  hierarchical (party → priority badge → arguments) display, "טיעונים"
  tab on the case page, "חשב/חשב מחדש" buttons.
* scripts/backfill_legal_arguments.py + SCRIPTS.md entry — dry-run
  found 8 candidate cases including 1017/1018/1019.

## Open follow-ups (intentionally deferred)
* npm run api:types in web-ui (CLAUDE.md flow) — recommended before
  the next UI commit; not required for backend deployment.
* Run backfill_legal_arguments.py --apply once the container picks up
  the new aggregator service.
* webhook on missing-precedents upload-close to Paperclip (optional).

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

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

@@ -128,7 +128,7 @@ async def case_create(
     hearing_date: str = "",
     notes: str = "",
     expected_outcome: str = "",
-    practice_area: str = "appeals_committee",
+    practice_area: str = "",
     appeal_subtype: str = "",
 ) -> str:
     """יצירת תיק ערר חדש.
@@ -145,7 +145,9 @@ async def case_create(
         hearing_date: תאריך דיון (YYYY-MM-DD)
         notes: הערות
         expected_outcome: תוצאה צפויה (rejection/partial_acceptance/full_acceptance/betterment_levy)
-        practice_area: תחום משפטי (appeals_committee / national_insurance / labor_law)
+        practice_area: תחום משפטי — domain value (rishuy_uvniya / betterment_levy /
+                        compensation_197). ריק או "appeals_committee" = יוסק
+                        אוטומטית ממספר התיק (1xxx→רישוי, 8xxx→השבחה, 9xxx→197)
         appeal_subtype: סוג ערר (building_permit / betterment_levy / compensation_197).
                         ריק = יוסק אוטומטית ממספר התיק
     """
@@ -155,8 +157,18 @@ async def case_create(
     if hearing_date:
         h_date = date_type.fromisoformat(hearing_date)
 
-    # Resolve appeal_subtype: explicit override > auto-derive > 'unknown'
-    derived_subtype = pa.derive_subtype(case_number, practice_area)
+    # Auto-derive practice_area when missing or set to the legacy multi-tenant
+    # value. The DB's cases_practice_area_check rejects 'appeals_committee',
+    # so we MUST map it to a domain value before INSERT. If derivation fails
+    # (unknown case number format), fall back to '' which the constraint allows.
+    if not practice_area or practice_area == "appeals_committee":
+        practice_area = pa.derive_domain_practice_area(case_number)
+
+    # Resolve appeal_subtype: explicit override > auto-derive > 'unknown'.
+    # derive_subtype_with_blam inspects the subject to detect בל"מ
+    # (בקשה להארכת מועד) and returns an extension_request_* variant when
+    # appropriate. Falls back to regular derive_subtype when subject is empty.
+    derived_subtype = pa.derive_subtype_with_blam(case_number, subject, practice_area)
     if not appeal_subtype:
         appeal_subtype = derived_subtype
     pa.validate(practice_area, appeal_subtype)