feat(storage): X14 Phase 2c — route remaining sync write-sites through storage.py

Completes the write-side rewiring (INV-STG1) for the call-sites that run in
synchronous contexts, via a new blocking facade in storage.py
(put_bytes_sync / put_file_sync — asyncio.run, or a worker thread when a loop
is already running):
- services/extractor.py: multimodal thumbnail JPEGs → DERIVED (rendered in a
  to_thread worker)
- services/docx_reviser.py: track-changes save (_save_docx_xml) + empty-diff
  copy (copy_with_revisions) → DOCUMENTS
- services/docx_retrofit.py: in-place retrofit backup → DOCUMENTS

Each site keeps a fallback to a direct disk write when the target path is
outside DATA_DIR (caller-provided). Under the default STORAGE_BACKEND=
filesystem the bytes land exactly where they did before — zero behaviour
change.

Also: mcp_env_catalog MINIO_ENDPOINT default updated to the durable
container-name endpoint (http://minio-bx2ykvw94xbutsex41hz4vv8:9000), matching
the Coolify "Connect to Predefined Network" change made for network durability.

All binary write-sites now flow through storage.py. git-tracked text
(case.json/notes/research-md/draft-md) stays on disk by design (INV-STG7);
court-fetch temp files are ephemeral.

tests: +2 (thumbnail renderer routes through storage; put_bytes_sync
round-trip); 55 storage/docx/track-changes green; 244 collected, no import
breakage.

Keeps G2; completes INV-STG1 write coverage. Spec: docs/spec/X14-storage-minio.md.

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

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

@@ -37,6 +37,7 @@ is absent (the default filesystem backend needs nothing extra).
 """
 from __future__ import annotations
 
+import asyncio
 import logging
 import shutil
 import tempfile
@@ -470,3 +471,43 @@ def local_path(key, *, bucket=Bucket.DOCUMENTS) -> Path | None:
 
 async def ensure_local(key, *, bucket=Bucket.DOCUMENTS) -> Path:
     return await get_storage().ensure_local(key, bucket=bucket)
+
+
+# ── synchronous facade ─────────────────────────────────────────────
+# A few legacy writers are plain sync functions (track-changes save, retrofit
+# backup, the multimodal thumbnail renderer which runs in a worker thread via
+# asyncio.to_thread). They go through the same layer via this blocking shim so
+# INV-STG1 holds everywhere.
+
+def _run_coro_blocking(coro):
+    """Run a storage coroutine to completion from synchronous code.
+
+    No running loop in this thread (the common case — sync helpers, or a
+    to_thread worker) → asyncio.run. If a loop *is* already running here, the
+    coroutine is offloaded to a fresh thread so we never deadlock the loop."""
+    try:
+        asyncio.get_running_loop()
+    except RuntimeError:
+        return asyncio.run(coro)
+    box: dict = {}
+
+    def _worker():
+        box["value"] = asyncio.run(coro)
+
+    import threading
+    t = threading.Thread(target=_worker)
+    t.start()
+    t.join()
+    return box["value"]
+
+
+def put_bytes_sync(key, data, *, bucket=Bucket.DOCUMENTS, content_type=None,
+                   metadata=None) -> str:
+    return _run_coro_blocking(
+        put_bytes(key, data, bucket=bucket, content_type=content_type, metadata=metadata))
+
+
+def put_file_sync(src, key, *, bucket=Bucket.DOCUMENTS, content_type=None,
+                  metadata=None) -> str:
+    return _run_coro_blocking(
+        put_file(src, key, bucket=bucket, content_type=content_type, metadata=metadata))