fix(glyph): use full MCP endpoint URL for tool server connection

Open WebUI posts to the url directly without appending the path field
for MCP type connections. Move /mcp into the url itself.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: stackptr

hosts/glyph/services/open-webui.nix

@@ -198,8 +198,8 @@ in {
       TOOL_SERVER_CONNECTIONS = builtins.toJSON [
         {
           type = "mcp";
-          url = "http://localhost:8090";
-          path = "mcp";
+          url = "http://localhost:8090/mcp";
+          path = "";
           auth_type = "none";
           key = "";
           config.enable = true;