feat(corpus): Stage A — corpus tagging fixes + prevention layer

מתקן את הבאג של תיוג שגוי לועדות ערר ומונע חזרתו:

**Code changes:**
* New MCP tool `internal_decision_upload` (chair_name+district required)
  — sole supported path for ingesting committee decisions; tags
  source_kind='internal_committee' automatically.
* Citation guard in `precedent_library_upload` rejects citations starting
  with "ערר" or "בל\"מ" with a directive to use internal_decision_upload.
* `practice_area.py` taxonomy unification: PRACTICE_AREAS now accepts
  both multi-tenant (appeals_committee/national_insurance/labor_law)
  and domain (rishuy_uvniya/betterment_levy/compensation_197) values.
  New helper `to_db_practice_area(multi_tenant, subtype) -> domain`.

**Agent docs:**
* legal-researcher (+5K): upload-tool decision flowchart, code samples
  per source_kind, district enum (ירושלים/מרכז/תל אביב/צפון/דרום/חיפה/ארצי)
* legal-ceo, legal-analyst, legal-writer, legal-qa, HEARTBEAT — taxonomy
  awareness + source_kind-aware citation patterns + research_complete
  as valid status.
* Fixed two pre-existing wrong practice_area values in examples
  (histael_hashbacha→betterment_levy, pitsuim_197→compensation_197).

Closes TaskMaster #30(parts), #38(parts), #39 (root cause).
DB-side backfill + CHECK constraints applied directly via psql:
* 11 cases.practice_area corrected (1xxx→rishuy, 8xxx→betterment)
* 6 case_law records reclassified external_upload→internal_committee
  with inferred district
* 6 chair_name backfilled from full_text (5 שרית אריאלי + 1 דפנה תמיר)
* 88 new halachot extracted for newly-uploaded precedents
  (אנטרים + ירושלים שקופה 1112/22 + אגא וכט)
* CHECK constraints: cases.practice_area enum, case_law internal⇒district

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

mcp-server/src/legal_mcp/services/practice_area.py

@@ -2,14 +2,34 @@
 
 Two orthogonal axes used to separate legal domains across the system:
 
-  practice_area  — top-level domain (multi-tenant axis). Examples:
-                   appeals_committee, national_insurance, labor_law.
-  appeal_subtype — refines within a domain. For appeals_committee:
-                   building_permit (1xxx), betterment_levy (8xxx),
-                   compensation_197 (9xxx), unknown.
+  practice_area  — top-level domain. **Two taxonomies coexist** (see below).
+  appeal_subtype — refines within a domain.
 
-Both columns are denormalized into documents/chunks/decisions/style_corpus
-so vector searches can filter cheaply.
+⚠️  TWO TAXONOMIES — DO NOT CONFUSE
+==================================
+
+A. **Multi-tenant axis** (legacy, used in routing logic):
+   - ``appeals_committee``  — the legal-ai instance for Daphna's committee
+   - ``national_insurance`` — future / hypothetical other tenants
+   - ``labor_law``           — future
+   When this axis is used, ``appeal_subtype`` carries the actual domain:
+   ``building_permit`` (1xxx), ``betterment_levy`` (8xxx),
+   ``compensation_197`` (9xxx).
+
+B. **Domain axis** (DB columns ``case_law.practice_area``,
+   ``cases.practice_area`` — what tests, validators, and CHECK constraints
+   actually use):
+   - ``rishuy_uvniya``     — רישוי ובנייה (1xxx)
+   - ``betterment_levy``   — היטל השבחה (8xxx)
+   - ``compensation_197``  — פיצויים סעיף 197 (9xxx)
+
+Use ``to_db_practice_area(multi_tenant_pa, appeal_subtype)`` to convert
+from axis A to axis B before writing to the DB.
+
+Background: TaskMaster #30 (sub-bug ב) — many ``case_law`` rows stored
+``appeals_committee`` (axis A) where they should have stored a domain
+value (axis B). The migration backfill plus CHECK constraints close the
+gap, and this module now validates **both** namespaces.
 """
 
 from __future__ import annotations
@@ -18,12 +38,23 @@ import re
 
 # ── Enums ──────────────────────────────────────────────────────────
 
-PRACTICE_AREAS: set[str] = {
+# Multi-tenant axis (legacy)
+MULTI_TENANT_PRACTICE_AREAS: set[str] = {
     "appeals_committee",
     "national_insurance",
     "labor_law",
 }
 
+# Domain axis (matches DB constraints on case_law/cases)
+DOMAIN_PRACTICE_AREAS: set[str] = {
+    "rishuy_uvniya",
+    "betterment_levy",
+    "compensation_197",
+}
+
+# Union — what ``validate()`` accepts for backward-compat
+PRACTICE_AREAS: set[str] = MULTI_TENANT_PRACTICE_AREAS | DOMAIN_PRACTICE_AREAS
+
 APPEALS_COMMITTEE_SUBTYPES: set[str] = {
     "building_permit",
     "betterment_levy",
@@ -38,8 +69,42 @@ SUBTYPES_BY_AREA: dict[str, set[str]] = {
     "appeals_committee": APPEALS_COMMITTEE_SUBTYPES,
     "national_insurance": {"unknown"},
     "labor_law": {"unknown"},
+    # Domain values — subtype is implicit in the value itself
+    "rishuy_uvniya": {"building_permit", "unknown"},
+    "betterment_levy": {"betterment_levy", "unknown"},
+    "compensation_197": {"compensation_197", "unknown"},
 }
 
+# Mapping: (multi_tenant_pa, appeal_subtype) → domain_pa
+_SUBTYPE_TO_DOMAIN: dict[str, str] = {
+    "building_permit": "rishuy_uvniya",
+    "betterment_levy": "betterment_levy",
+    "compensation_197": "compensation_197",
+}
+
+
+def to_db_practice_area(practice_area: str, appeal_subtype: str = "") -> str:
+    """Convert a multi-tenant practice_area + appeal_subtype to the
+    domain value stored in DB columns (case_law/cases).
+
+    Returns ``""`` when the input cannot be mapped — callers should
+    handle this rather than letting ``""`` propagate silently to the DB.
+
+    Examples:
+        >>> to_db_practice_area("appeals_committee", "building_permit")
+        'rishuy_uvniya'
+        >>> to_db_practice_area("rishuy_uvniya")
+        'rishuy_uvniya'
+        >>> to_db_practice_area("appeals_committee")
+        ''
+    """
+    pa = (practice_area or "").strip()
+    if pa in DOMAIN_PRACTICE_AREAS:
+        return pa
+    if pa == "appeals_committee":
+        return _SUBTYPE_TO_DOMAIN.get((appeal_subtype or "").strip(), "")
+    return ""
+
 
 # ── Derivation ─────────────────────────────────────────────────────