Add CMPA (betterment levy) training support and update methodology

Support ingestion of betterment levy (היטל השבחה) decisions into a
separate training corpus (CMPA). Key changes:

- Add .doc file extraction via LibreOffice conversion in extractor
- Add practice_area/appeal_subtype columns to style_corpus table
- Route training files to cmp/ or cmpa/ subdirs based on appeal subtype
- Fix derive_subtype to handle ARAR-YY-NNNN format (was matching year digit)
- Expose practice_area/appeal_subtype params in MCP upload_training tool
- Add appeal_subtype filter to analyze_style for per-type style analysis
- Update betterment levy methodology in lessons.py: checklist (from generic
  to corpus-based), opening/closing strategies, and discussion rules

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

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

@@ -43,14 +43,17 @@ SUBTYPES_BY_AREA: dict[str, set[str]] = {
 
 # ── Derivation ─────────────────────────────────────────────────────
 
-_FIRST_DIGIT = re.compile(r"^\s*(\d)")
-
 _APPEALS_COMMITTEE_DIGIT_TO_SUBTYPE = {
     "1": "building_permit",
     "8": "betterment_levy",
     "9": "compensation_197",
 }
 
+# Match the case number (last numeric group) in formats like:
+#   ARAR-25-8126, ARAR-24-01-8007-33, 8126/25, 1170, ערר 1024-25
+_CASE_NUM = re.compile(r"(?:ARAR[-\s]*\d{2}[-\s]*(?:\d{2}[-\s]*)?)(\d{4})", re.IGNORECASE)
+_PLAIN_NUM = re.compile(r"(\d{4})")
+
 
 def derive_subtype(case_number: str, practice_area: str = DEFAULT_PRACTICE_AREA) -> str:
     """Infer the appeal_subtype from case_number.
@@ -58,15 +61,20 @@ def derive_subtype(case_number: str, practice_area: str = DEFAULT_PRACTICE_AREA)
     For appeals_committee, the convention is:
       1xxx → building_permit, 8xxx → betterment_levy, 9xxx → compensation_197.
 
-    For other practice areas there is no public numbering convention yet,
-    so we return 'unknown' until a real rule is defined.
+    Handles multiple formats: ARAR-25-8126, 8126/25, 1170, ערר 1024-25.
     """
     if practice_area != "appeals_committee":
         return "unknown"
-    m = _FIRST_DIGIT.match(case_number or "")
+    cn = case_number or ""
+    # Try ARAR format first (extracts the 4-digit case number after year prefix)
+    m = _CASE_NUM.search(cn)
+    if not m:
+        # Fallback: first 4-digit number in the string
+        m = _PLAIN_NUM.search(cn)
     if not m:
         return "unknown"
-    return _APPEALS_COMMITTEE_DIGIT_TO_SUBTYPE.get(m.group(1), "unknown")
+    first_digit = m.group(1)[0]
+    return _APPEALS_COMMITTEE_DIGIT_TO_SUBTYPE.get(first_digit, "unknown")
 
 
 # ── Validation ─────────────────────────────────────────────────────