feat(audit): log_action_safe + V22 blocks_stale + citation resolver (FU-7)

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

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

@@ -1106,6 +1106,16 @@ CREATE INDEX IF NOT EXISTS idx_case_law_searchable ON case_law (searchable);
 """
 
 
+# ── V22: cases.blocks_stale — DOCX↔blocks drift flag (GAP-17 / INV-EX1) ──
+# Set true when revise_draft/apply_user_edit make active_draft_path the live
+# source-of-truth without re-syncing decision_blocks; cleared when blocks are
+# re-exported or re-saved. Surfaced by health-check. Source-of-truth remains
+# decision_blocks — this only flags known drift (no fragile DOCX→blocks reparse).
+SCHEMA_V22_SQL = """
+ALTER TABLE cases ADD COLUMN IF NOT EXISTS blocks_stale boolean NOT NULL DEFAULT false;
+"""
+
+
 async def _run_schema_migrations(pool: asyncpg.Pool) -> None:
     async with pool.acquire() as conn:
         await conn.execute(SCHEMA_SQL)
@@ -1130,7 +1140,8 @@ async def _run_schema_migrations(pool: asyncpg.Pool) -> None:
         await conn.execute(SCHEMA_V19_SQL)
         await conn.execute(SCHEMA_V20_SQL)
         await conn.execute(SCHEMA_V21_SQL)
-    logger.info("Database schema initialized (v1-v21)")
+        await conn.execute(SCHEMA_V22_SQL)
+    logger.info("Database schema initialized (v1-v22)")
 
 
 async def init_schema() -> None:
@@ -1206,6 +1217,35 @@ async def get_active_draft_path(case_id: UUID) -> str | None:
     return row["active_draft_path"] if row else None
 
 
+async def mark_blocks_stale(case_id: UUID, stale: bool) -> None:
+    """Flag/clear DOCX↔blocks drift for a case (GAP-17)."""
+    pool = await get_pool()
+    async with pool.acquire() as conn:
+        await conn.execute(
+            "UPDATE cases SET blocks_stale = $1, updated_at = now() WHERE id = $2",
+            stale, case_id,
+        )
+
+
+async def resolve_citation_case_law_ids(ids) -> dict:
+    """Structural citation→corpus resolution (GAP-20 / INV-AUD3).
+
+    Given case_law_id values referenced by a decision's citations/provenance,
+    split into resolvable (exist in case_law) vs unresolvable.
+    """
+    resolved, unresolved = [], []
+    pool = await get_pool()
+    async with pool.acquire() as conn:
+        for cid in ids:
+            try:
+                exists = await conn.fetchval(
+                    "SELECT EXISTS(SELECT 1 FROM case_law WHERE id = $1)", cid)
+            except Exception:
+                exists = False
+            (resolved if exists else unresolved).append(cid)
+    return {"resolved": resolved, "unresolved": unresolved}
+
+
 def _normalize_case_number(s: str) -> str:
     """Canonicalise a case number for tolerant lookup.