feat(storage): X14 Phase 2b — route extracted-text + async DOCX exports through storage.py

Continue the write-site rewiring onto the unified storage layer (INV-STG1):
- services/processor.py: extracted-text .txt → DERIVED bucket (a derived
  artifact; the DB column is the source of truth per INV-STG5, so the write
  stays non-fatal)
- services/docx_exporter.py (export_decision): DOCX → DOCUMENTS bucket via
  BytesIO → put_bytes, with a fallback to a direct disk write when the caller
  passes an output_path outside DATA_DIR
- services/analysis_docx_exporter.py (build_analysis_docx): same pattern;
  out_path is always under DATA_DIR

Under the default STORAGE_BACKEND=filesystem the bytes land at the exact
legacy path (put_bytes → DATA_DIR/key), so behaviour is unchanged. The
disk-reading bits that must stay for now (export_dir glob in _next_version)
are kept; storage-native versioning is a cutover concern.

Still on disk (sync call-sites, follow-up Phase 2c): docx_reviser
(track-changes), docx_retrofit backup, and multimodal thumbnails (rendered in
a to_thread). git-tracked text (case.json/notes/research-md/draft-md) stays on
disk by design (INV-STG7).

tests: 38 storage + docx tests green (incl. test_export_qa_gate /
test_docx_exporter_bookmarks which exercise the real export path); 242
collected, no import breakage.

Keeps G2; advances INV-STG1. 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/analysis_docx_exporter.py

@@ -21,6 +21,7 @@ Output: data/cases/{case_number}/exports/ניתוח-משפטי-v{N}.docx
 
 from __future__ import annotations
 
+import io
 import re
 from pathlib import Path
 from typing import Any
@@ -34,7 +35,7 @@ from docx.text.paragraph import Paragraph
 from docx.text.run import Run
 
 from legal_mcp import config
-from legal_mcp.services import db, research_md
+from legal_mcp.services import db, research_md, storage
 
 
 def _mark_run_rtl(run: Run) -> None:
@@ -494,10 +495,19 @@ async def build_analysis_docx(case_number: str) -> Path:
                 continue
             _emit_content_line(doc, raw)
 
-    # Save versioned
+    # Save versioned through the storage layer (INV-STG1). export_dir.mkdir +
+    # the glob in _next_version still read disk (correct under filesystem/dual;
+    # storage-native versioning is a cutover concern). out_path is always under
+    # DATA_DIR, so the bytes land exactly where they did before.
     export_dir = case_dir / "exports"
     export_dir.mkdir(parents=True, exist_ok=True)
     version = _next_version(export_dir)
     out_path = export_dir / f"ניתוח-משפטי-v{version}.docx"
-    doc.save(str(out_path))
+    buf = io.BytesIO()
+    doc.save(buf)
+    await storage.put_bytes(
+        out_path.relative_to(config.DATA_DIR).as_posix(), buf.getvalue(),
+        bucket=storage.Bucket.DOCUMENTS,
+        content_type="application/vnd.openxmlformats-officedocument.wordprocessingml.document",
+    )
     return out_path