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/server.py

@@ -54,6 +54,8 @@ from legal_mcp.tools import (  # noqa: E402
     cases, documents, search, drafting, workflow, precedents,
     precedent_library as plib,
     internal_decisions as int_tools,
+    legal_arguments as la_tools,
+    missing_precedents as mp_tools,
 )
 
 
@@ -364,6 +366,28 @@ async def get_claims(
     return await documents.get_claims(case_number, party_role)
 
 
+# Legal arguments — aggregated (de-duped) propositions
+@mcp.tool()
+async def aggregate_claims_to_arguments(
+    case_number: str,
+    force: bool = False,
+) -> str:
+    """כינוס פרופוזיציות גולמיות (claims) לטיעונים משפטיים מובחנים — ~6-12 לכל צד.
+
+    משתמש ב-Claude headless לסיווג ואיגוד. force=True מוחק טיעונים קיימים לפני חישוב מחדש.
+    """
+    return await la_tools.aggregate_claims_to_arguments(case_number, force=force)
+
+
+@mcp.tool()
+async def get_legal_arguments(
+    case_number: str,
+    party: str = "",
+) -> str:
+    """שליפת טיעונים משפטיים מאוגדים. party: appellant/respondent/committee/permit_applicant (ריק=הכל)."""
+    return await la_tools.get_legal_arguments(case_number, party)
+
+
 # References
 @mcp.tool()
 async def extract_references(
@@ -703,6 +727,82 @@ async def internal_decision_upload(
     )
 
 
+# ── Missing precedents (TaskMaster #35) ───────────────────────────
+
+
+@mcp.tool()
+async def missing_precedent_create(
+    citation: str,
+    case_number: str = "",
+    cited_in_document_id: str = "",
+    cited_by_party: str = "unknown",
+    cited_by_party_name: str = "",
+    legal_topic: str = "",
+    legal_issue: str = "",
+    claim_quote: str = "",
+    case_name: str = "",
+    notes: str = "",
+) -> str:
+    """תיעוד פסיקה שצוטטה בכתבי הטענות אך אינה בקורפוס.
+
+    שימוש: סוכן המחקר (legal-researcher) קורא לזה כשהוא מזהה ציטוט שלא
+    ניתן לאמת מול הקורפוס. הרשומה נשארת 'open' עד שהיו"ר מעלה את הפסיקה.
+    cited_by_party: appellant / respondent / committee / permit_applicant / unknown.
+    דה-דופ אוטומטי: ציטוט+תיק זהים → מחזיר את הרשומה הקיימת.
+    """
+    return await mp_tools.missing_precedent_create(
+        citation=citation,
+        case_number=case_number,
+        cited_in_document_id=cited_in_document_id,
+        cited_by_party=cited_by_party,
+        cited_by_party_name=cited_by_party_name,
+        legal_topic=legal_topic,
+        legal_issue=legal_issue,
+        claim_quote=claim_quote,
+        case_name=case_name,
+        notes=notes,
+    )
+
+
+@mcp.tool()
+async def missing_precedent_list(
+    case_number: str = "",
+    status: str = "open",
+    legal_topic: str = "",
+    limit: int = 50,
+) -> str:
+    """רשימת פסיקות חסרות לתיק או בכלל. status: open/uploaded/closed/irrelevant.
+
+    שימוש: היו"ר רואה מה ממתין להעלאה; הסוכן מאשר שלא יוצר כפילויות.
+    """
+    return await mp_tools.missing_precedent_list(
+        case_number=case_number,
+        status=status,
+        legal_topic=legal_topic,
+        limit=limit,
+    )
+
+
+@mcp.tool()
+async def missing_precedent_close(
+    id: str,
+    linked_case_law_id: str = "",
+    notes: str = "",
+    status: str = "closed",
+) -> str:
+    """סגירת רשומת פסיקה חסרה לאחר העלאה לקורפוס.
+
+    status: closed (הועלה ונקשר) / uploaded (הועלה, ממתין לקישור) /
+    irrelevant (היו"ר החליט שזה לא רלוונטי לקורפוס).
+    """
+    return await mp_tools.missing_precedent_close(
+        id=id,
+        linked_case_law_id=linked_case_law_id,
+        notes=notes,
+        status=status,
+    )
+
+
 @mcp.tool()
 async def record_chair_feedback(
     case_number: str,