Auto-strip Nevo preambles and separate style analysis per appeal subtype

- Add strip_nevo_preamble() to extractor.py — auto-removes Nevo database
  headers (bibliography, legislation, mini-ratio) during training upload
- Add appeal_subtype column to style_patterns table — patterns are now
  stored per subtype instead of globally mixed
- Update clear_style_patterns() to support subtype-scoped deletion
- Pass appeal_subtype through analyze_corpus → store → upsert pipeline

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

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

@@ -116,6 +116,7 @@ CREATE TABLE IF NOT EXISTS style_patterns (
     frequency INTEGER DEFAULT 1,
     context TEXT DEFAULT '',
     examples JSONB DEFAULT '[]',
+    appeal_subtype TEXT DEFAULT '',
     created_at TIMESTAMPTZ DEFAULT now()
 );
 
@@ -165,6 +166,9 @@ ALTER TABLE cases ADD COLUMN IF NOT EXISTS appeal_subtype TEXT DEFAULT '';
 ALTER TABLE style_corpus ADD COLUMN IF NOT EXISTS practice_area TEXT DEFAULT 'appeals_committee';
 ALTER TABLE style_corpus ADD COLUMN IF NOT EXISTS appeal_subtype TEXT DEFAULT '';
 
+-- הרחבת style_patterns עם appeal_subtype לניתוח סגנון נפרד לכל סוג ערר
+ALTER TABLE style_patterns ADD COLUMN IF NOT EXISTS appeal_subtype TEXT DEFAULT '';
+
 -- טבלת qa_results
 CREATE TABLE IF NOT EXISTS qa_results (
     id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
@@ -973,12 +977,14 @@ async def upsert_style_pattern(
     pattern_text: str,
     context: str = "",
     examples: list[str] | None = None,
+    appeal_subtype: str = "",
 ) -> None:
     pool = await get_pool()
     async with pool.acquire() as conn:
         existing = await conn.fetchrow(
-            "SELECT id, frequency FROM style_patterns WHERE pattern_type = $1 AND pattern_text = $2",
-            pattern_type, pattern_text,
+            "SELECT id, frequency FROM style_patterns "
+            "WHERE pattern_type = $1 AND pattern_text = $2 AND appeal_subtype = $3",
+            pattern_type, pattern_text, appeal_subtype,
         )
         if existing:
             await conn.execute(
@@ -987,18 +993,27 @@ async def upsert_style_pattern(
             )
         else:
             await conn.execute(
-                """INSERT INTO style_patterns (pattern_type, pattern_text, context, examples)
-                   VALUES ($1, $2, $3, $4)""",
+                """INSERT INTO style_patterns (pattern_type, pattern_text, context, examples, appeal_subtype)
+                   VALUES ($1, $2, $3, $4, $5)""",
                 pattern_type, pattern_text, context,
                 json.dumps(examples or []),
+                appeal_subtype,
             )
 
 
-async def clear_style_patterns() -> None:
-    """Delete all existing style patterns (used before re-analysis)."""
+async def clear_style_patterns(appeal_subtype: str = "") -> None:
+    """Delete style patterns, optionally filtered by appeal_subtype.
+
+    Empty appeal_subtype = delete ALL patterns.
+    """
     pool = await get_pool()
     async with pool.acquire() as conn:
-        await conn.execute("DELETE FROM style_patterns")
+        if appeal_subtype:
+            await conn.execute(
+                "DELETE FROM style_patterns WHERE appeal_subtype = $1", appeal_subtype
+            )
+        else:
+            await conn.execute("DELETE FROM style_patterns")
 
 
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