Add native chat background and guarded HA YAML access

platform/openwebui/install-models.sh

@@ -72,6 +72,16 @@ if not owner:
         )
     owner = admins[0][0]
 
+# Use Open WebUI's native per-user chat background.  Keeping the value in the
+# user's normal settings means the built-in contrast overlay, mobile layout
+# and future UI migrations continue to work; custom.css must not replace this
+# layer.
+row = con.execute("select settings from user where id=?", (owner,)).fetchone()
+if not row:
+    raise SystemExit("OpenWebUI model owner does not exist in user table.")
+user_settings = json.loads(row[0] or "{}")
+user_settings.setdefault("ui", {})["backgroundImageUrl"] = "/static/midnight-aurora.svg"
+
 now = int(time.time())
 filter_ids = [
     "reasoning_default_off",
@@ -226,6 +236,10 @@ def set_config(key, value):
     )
 
 with con:
+    con.execute(
+        "update user set settings=? where id=?",
+        (json.dumps(user_settings, ensure_ascii=False), owner),
+    )
     router_api_key = os.environ.get("OPENWEBUI_ROUTER_API_KEY", "")
     if router_api_key:
         set_config("openai.enable", True)