Phase 4.5: practice area integration in the Next.js UI

Backend commit 26d09d6 introduced a multi-tenant axis (practice_area +
appeal_subtype) that the vanilla UI picked up but the new Next.js
rewrite did not. Close the gap in the screens we already shipped so
future search/filter work in Phase 5 has the right data on screen.

- lib/practice-area.ts — new: enum + label maps + deriveSubtype(),
  mirrors mcp-server/src/legal_mcp/services/practice_area.py.
- lib/schemas/case.ts — two new z.enum fields on caseCreateSchema.
- lib/api/cases.ts — Case / CaseDetail gain practice_area and
  appeal_subtype as optional (cached pre-migration responses still
  parse cleanly).
- wizard/case-wizard.tsx — basics step gains a practice_area dropdown
  (future domains disabled with "(בקרוב)") and an appeal_subtype
  dropdown with auto-fill effect tracking a userTouchedSubtype ref,
  same behaviour as wireSubtypeAutofill() in the vanilla UI.
- cases/case-header.tsx — gold badge next to the status shows
  "ועדת ערר · רישוי ובנייה" when both fields are populated.
- cases/cases-table.tsx — new "תחום" column showing subtype label
  (dash for unknown). No filter yet — that's phase 5 when a second
  domain actually exists.

Plan: ~/.claude/plans/woolly-cooking-graham.md

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

web-ui/src/lib/api/cases.ts

@@ -11,6 +11,7 @@
 import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
 import { apiRequest } from "./client";
 import type { CaseCreateInput, CaseUpdateInput } from "@/lib/schemas/case";
+import type { PracticeArea, AppealSubtype } from "@/lib/practice-area";
 
 export type CaseStatus =
   | "new"
@@ -35,6 +36,9 @@ export type Case = {
   expected_outcome?: string | null;
   created_at?: string;
   updated_at?: string;
+  /* Multi-tenant axis — populated by backfill + server-side derive */
+  practice_area?: PracticeArea;
+  appeal_subtype?: AppealSubtype;
   /* Present when loaded with detail=true */
   document_count?: number;
   processing_count?: number;