Load the God's Eye View panel through the MCP server

Hosts serve panels from their own sites and may refuse other addresses;
Codex refuses any address on the user's machine. The panel now never
requests the app's server: it loads the app's panel build and data
through panel_request, a tool only the panel may call, which requests
the path from the app's server. One path in every host; only map
providers load directly.

npm run build:panel writes the panel build to dist/panel, served at
/panel/: one app script, one stylesheet, Cesium's script, and Cesium's
workers as one script Cesium runs from memory. Tools may now be marked
app-only. The panel CORS rules are gone.

src/tools/services.js

@@ -3,7 +3,7 @@
  * factories and the application request services. `fetchImpl` must resolve
  * the sources' relative `/api/...` paths; in a browser the page's own fetch
  * does, and elsewhere a caller supplies a resolving fetch. `appUrl` is the
- * address the app is served from.
+ * address the app is served from; `app.fetch` requests the app's own paths.
  */
 
 import { createAlprTileSource } from '../layers/alpr/source.js';
@@ -45,7 +45,7 @@ export function createToolServices({ fetchImpl, appUrl }) {
     throw new TypeError('A fetch implementation is required');
   const requests = createApplicationRequestServices({ fetchImpl });
   return {
-    app: { baseUrl: appUrl },
+    app: { baseUrl: appUrl, fetch: fetchImpl },
     earthquakes: createUsgsEarthquakeSource({ fetchImpl }),
     fires: createFirmsSource({ fetchImpl }),
     launches: createLaunchSource({ fetchImpl }),