Update Antigravity provider config and headers

- Simplify ANTIGRAVITY_HEADERS to dynamic User-Agent only
- Use IDE_TYPE, PLUGIN_TYPE enums and getPlatformEnum() in metadata
- Update antigravity baseUrl to sandbox endpoint
- Bump User-Agent version from 1.104.0 to 1.107.0
- Remove redundant header spread in AntigravityExecutor

Made-with: Cursor

open-sse/config/providers.js

@@ -98,10 +98,10 @@ export const PROVIDERS = {
   antigravity: {
     baseUrls: [
       "https://daily-cloudcode-pa.googleapis.com",
-      "https://cloudcode-pa.googleapis.com",
+      "https://daily-cloudcode-pa.sandbox.googleapis.com",
     ],
     format: "antigravity",
-    headers: { "User-Agent": `antigravity/1.104.0 ${platform()}/${arch()}` },
+    headers: { "User-Agent": `antigravity/1.107.0 ${platform()}/${arch()}` },
     clientId: "1071006060591-tmhssin2h21lcre235vtolojh4g403ep.apps.googleusercontent.com",
     clientSecret: "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"
   },