Dashboard Studio 1.10.0: phone dashboards, room card, changelog

- Phone dashboards: a 4-column layout designed at phone width, with
  conversion both ways; on phones the top bar is hidden and comes back
  with a touch-and-hold on an empty spot
- Room card built from Home Assistant areas (area, device and entity
  registries): climate, lights on with an all-lights toggle, thermostat,
  open doors and windows, motion, media, and device buttons
- CHANGELOG.md for Home Assistant's Changelog tab, served at
  /api/changelog and shown under About > What's new

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

dashboard_studio/server/main.py

@@ -141,6 +141,14 @@ async def users(request):
     return web.json_response([{"id": k, **v} for k, v in load_users().items()], headers={"Cache-Control": "no-store"})
 
 
+async def changelog(request):
+    try:
+        text = (APP_DIR / "CHANGELOG.md").read_text()
+    except OSError:
+        text = ""
+    return web.Response(text=text, content_type="text/markdown", headers={"Cache-Control": "no-store"})
+
+
 async def version(request):
     return web.json_response({"version": VERSION}, headers={"Cache-Control": "no-store"})
 
@@ -248,6 +256,7 @@ def make_app():
     app = web.Application(middlewares=[ingress_only], client_max_size=8 * 1024 * 1024)
     app.router.add_get("/", index)
     app.router.add_get("/api/version", version)
+    app.router.add_get("/api/changelog", changelog)
     app.router.add_get("/api/whoami", whoami)
     app.router.add_get("/api/users", users)
     app.router.add_get("/api/dashboards", get_dashboards)