fix(corpus): חיפה is its own district, not folded into צפון (G2)

Haifa (מחוז חיפה) and the North (מחוז הצפון) are separate Israeli planning
districts, each with its own appeals committee. Two divergent bugs collapsed
Haifa into צפון:
- services/internal_decisions.py _VALID_DISTRICTS omitted "חיפה" (while the
  tools-layer VALID_DISTRICTS and db.py citation-abbrev map both include it —
  a G2 single-source-of-truth divergence)
- _COURT_TO_DISTRICT mapped "חיפה" -> "צפון", so Haifa courts derived צפון

Result: 2 Haifa committee decisions (1074-08-23, 8508-03-24) were mis-filed
under צפון, and "חיפה" never appeared as a district.

Changes:
- add "חיפה" to service _VALID_DISTRICTS
- _COURT_TO_DISTRICT: ("חיפה","צפון") -> ("חיפה","חיפה")
- SCHEMA_V43: reclassify legacy internal rows whose court mentions חיפה from
  צפון -> חיפה (normalize at source, G1; idempotent)

Verified against live DB (rollback txn): 2 rows move צפון(6)->צפון(4)+חיפה(2).

Invariants: G1 (normalize at source) · G2 (single source of truth for the
valid-district set — follow-up: consolidate the 3 divergent lists).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

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

@@ -28,14 +28,14 @@ logger = logging.getLogger(__name__)
 INTERNAL_DECISIONS_DIR = Path(config.DATA_DIR) / "internal-decisions"
 
 _VALID_PRACTICE_AREAS = frozenset({"", "rishuy_uvniya", "betterment_levy", "compensation_197"})
-_VALID_DISTRICTS = frozenset({"", "ירושלים", "מרכז", "תל אביב", "צפון", "דרום", "ארצי"})
+_VALID_DISTRICTS = frozenset({"", "ירושלים", "מרכז", "תל אביב", "חיפה", "צפון", "דרום", "ארצי"})
 
 _COURT_TO_DISTRICT = [
     ("ירושלים", "ירושלים"),
     ("תל אביב", "תל אביב"),
     ('ת"א', "תל אביב"),
     ("מרכז", "מרכז"),
-    ("חיפה", "צפון"),
+    ("חיפה", "חיפה"),
     ("צפון", "צפון"),
     ("דרום", "דרום"),
     ("ארצי", "ארצי"),