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>

web-ui/src/components/ui/accordion.tsx

@@ -0,0 +1,66 @@
+"use client"
+
+import * as React from "react"
+import { Accordion as AccordionPrimitive } from "radix-ui"
+import { ChevronDown } from "lucide-react"
+
+import { cn } from "@/lib/utils"
+
+function Accordion({
+  ...props
+}: React.ComponentProps<typeof AccordionPrimitive.Root>) {
+  return <AccordionPrimitive.Root data-slot="accordion" {...props} />
+}
+
+function AccordionItem({
+  className,
+  ...props
+}: React.ComponentProps<typeof AccordionPrimitive.Item>) {
+  return (
+    <AccordionPrimitive.Item
+      data-slot="accordion-item"
+      className={cn("border-b border-rule last:border-b-0", className)}
+      {...props}
+    />
+  )
+}
+
+function AccordionTrigger({
+  className,
+  children,
+  ...props
+}: React.ComponentProps<typeof AccordionPrimitive.Trigger>) {
+  return (
+    <AccordionPrimitive.Header className="flex">
+      <AccordionPrimitive.Trigger
+        data-slot="accordion-trigger"
+        className={cn(
+          "focus-visible:ring-ring/50 flex flex-1 items-start justify-between gap-4 rounded-md py-4 text-start text-sm font-medium transition-all outline-none hover:underline focus-visible:ring-[3px] disabled:pointer-events-none disabled:opacity-50 [&[data-state=open]>svg]:rotate-180",
+          className
+        )}
+        {...props}
+      >
+        {children}
+        <ChevronDown className="text-ink-muted pointer-events-none size-4 shrink-0 translate-y-0.5 transition-transform duration-200" />
+      </AccordionPrimitive.Trigger>
+    </AccordionPrimitive.Header>
+  )
+}
+
+function AccordionContent({
+  className,
+  children,
+  ...props
+}: React.ComponentProps<typeof AccordionPrimitive.Content>) {
+  return (
+    <AccordionPrimitive.Content
+      data-slot="accordion-content"
+      className="data-[state=closed]:animate-accordion-up data-[state=open]:animate-accordion-down overflow-hidden text-sm"
+      {...props}
+    >
+      <div className={cn("pt-0 pb-4", className)}>{children}</div>
+    </AccordionPrimitive.Content>
+  )
+}
+
+export { Accordion, AccordionItem, AccordionTrigger, AccordionContent }