Add PWA install badge for desktop and tablet (manifest, SW, Add to Home Screen).

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/app/main.py

@@ -128,6 +128,41 @@ _DIST = resolve_frontend_dist()
 if (_DIST / "assets").is_dir():
     app.mount("/assets", StaticFiles(directory=str(_DIST / "assets")), name="assets")
 
+_ICONS = _DIST / "icons"
+if _ICONS.is_dir():
+    app.mount("/icons", StaticFiles(directory=str(_ICONS)), name="icons")
+
+
+def _dist_file(name: str) -> Path:
+    return _DIST / name
+
+
+@app.get("/manifest.webmanifest")
+async def web_manifest():
+    path = _dist_file("manifest.webmanifest")
+    if not path.exists():
+        raise HTTPException(status_code=404, detail="manifest missing")
+    return FileResponse(
+        path,
+        media_type="application/manifest+json",
+        headers={"Cache-Control": "no-cache"},
+    )
+
+
+@app.get("/sw.js")
+async def service_worker():
+    path = _dist_file("sw.js")
+    if not path.exists():
+        raise HTTPException(status_code=404, detail="service worker missing")
+    return FileResponse(
+        path,
+        media_type="application/javascript",
+        headers={
+            "Cache-Control": "no-cache",
+            "Service-Worker-Allowed": "/",
+        },
+    )
+
 
 @app.get("/")
 async def index_page():