Improve document processing pipeline and agent workflows

- Add delete_document_chunks for reprocessing, save extracted text to disk
- Expand case directory structure (original/extracted/proofread/backup)
- Update classifier patterns (תגובה, הודעת עמדה)
- Fix proofreader agent paths for new directory layout
- Update HEARTBEAT to notify on every task completion
- Improve bidi_table with LRE/PDF directional embedding
- Add Paperclip project verification and auto-close setup issue
- Add auto-sync-cases.sh for Gitea synchronization

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

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

@@ -687,6 +687,16 @@ async def update_decision(decision_id: UUID, **fields) -> None:
 
 # ── Chunks & Vectors ───────────────────────────────────────────────
 
+async def delete_document_chunks(document_id: UUID) -> int:
+    """Delete all chunks for a document (used before reprocessing)."""
+    pool = await get_pool()
+    async with pool.acquire() as conn:
+        result = await conn.execute(
+            "DELETE FROM document_chunks WHERE document_id = $1", document_id
+        )
+        return int(result.split()[-1])  # e.g. "DELETE 5" -> 5
+
+
 async def store_chunks(
     document_id: UUID,
     case_id: UUID | None,