Rename extension and update context file name (#49)

- Updated Gemini CLI extension according to the latest updates.

Author: jackwotherspoon

gemini-extension.json

@@ -1,9 +1,7 @@
 {
-  "name": "google-maps-platform-gemini-cli-extension",
+  "name": "google-maps-platform",
   "version": "0.1.0",
-  "context": [
-    "GEMINI.md"
-  ],
+  "contextFileName": "GEMINI.md",
   "mcpServers": {
     "google-maps-platform-code-assist": {
       "command": "npx",
@@ -14,4 +12,4 @@
     }
   },
   "theme": "gmp-theme.json"
-}
+}