Add download button for analysis-and-research.md

New GET /api/cases/{n}/research/analysis/download endpoint returns the
raw markdown file. UI adds a "הורד ניתוח" button next to "חזרה לתיק"
on the compose page, visible only when analysis data is loaded.

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

web/app.py

@@ -1620,6 +1620,19 @@ async def api_research_analysis(case_number: str):
         raise HTTPException(500, f"שגיאה בעיבוד הקובץ: {e}")
 
 
+@app.get("/api/cases/{case_number}/research/analysis/download")
+async def api_research_analysis_download(case_number: str):
+    """Download the raw analysis-and-research.md file."""
+    path = _research_file_path(case_number)
+    if not path.exists():
+        raise HTTPException(404, "טרם בוצע ניתוח משפטי לתיק זה")
+    return FileResponse(
+        path,
+        media_type="text/markdown; charset=utf-8",
+        filename=f"analysis-{case_number}.md",
+    )
+
+
 class ChairPositionRequest(BaseModel):
     section_id: str
     position: str = ""