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/tests/test_storage_staging.py

@@ -46,3 +46,32 @@ def test_stage_file_default_subdir(_tmp_datadir):
     dest = run(ingest._stage_file(src, _tmp_datadir / "digests", ""))
     assert dest.parent == _tmp_datadir / "digests" / "other"
     assert dest.exists()
+
+
+def test_thumbnail_renderer_routes_through_storage(_tmp_datadir):
+    """extractor.render_pages_for_multimodal (a sync renderer) now persists the
+    JPEG thumbnail via the sync storage facade — under filesystem it must land
+    at the requested thumbnail_dir."""
+    fitz = pytest.importorskip("fitz")
+    from legal_mcp.services import extractor
+
+    pdf = _tmp_datadir / "doc.pdf"
+    d = fitz.open()
+    d.new_page(width=200, height=200)
+    d.save(str(pdf))
+    d.close()
+
+    thumb_dir = _tmp_datadir / "cases" / "1" / "thumbnails" / "docid"
+    out = extractor.render_pages_for_multimodal(pdf, embed_dpi=72, thumb_dpi=36,
+                                                thumbnail_dir=thumb_dir)
+    assert len(out) == 1
+    _img, thumb_path = out[0]
+    assert thumb_path == thumb_dir / "p001.jpg"
+    assert thumb_path.exists()  # written through storage.put_bytes_sync (DERIVED)
+    assert thumb_path.read_bytes()[:2] == b"\xff\xd8"  # JPEG magic
+
+
+def test_put_bytes_sync_roundtrip(_tmp_datadir):
+    src_key = "cases/1/exports/x.docx"
+    storage.put_bytes_sync(src_key, b"PK\x03\x04zip", bucket=storage.Bucket.DOCUMENTS)
+    assert (_tmp_datadir / src_key).read_bytes() == b"PK\x03\x04zip"