Add flight-map-canvas extension (#2482)

* Add flight-map-canvas extension

A canvas port of the Flight Map VSCode extension: a first-person
satellite terrain map flown with flight simulator controls, for
session breaks while an agent works.

The simulator under game/ is copied verbatim from the source
extension's media/ folder. That page already reached its host through
one seam - an acquireVsCodeApi() object and a placeholder in its head -
so extension.mjs fills that seam for the canvas: a loopback server that
injects a policy, the render configuration, and a shim translating
Server-Sent Events into the messages the page already handles.

Two agent actions: fly_to sends the flight to a capital, a geocoded
city, or a raw lat/lng, and picks a random capital when called with no
input; report_job shows the current job step under the HUD.

Adds the vendored three.min.js to the codespell skip list, matching the
existing entry for arcade-canvas's phaser.min.js.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

* Apply suggestions from code review

---------

Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

.github/plugin/marketplace.json

@@ -599,6 +599,12 @@
         "repo": "figma/mcp-server-guide"
       }
     },
+    {
+      "name": "flight-map-canvas",
+      "source": "extensions/flight-map-canvas",
+      "description": "A GitHub Copilot canvas that generates a view where Google Maps can be explored using 3D controls, as if a flight simulator. Agents can send the flight anywhere and report what they are working on.",
+      "version": "1.0.0"
+    },
     {
       "name": "flowstudio-power-automate",
       "source": "plugins/flowstudio-power-automate",