#433 fix(desktop): bake OAuth client IDs into main process at build time

Summary

• Fixed desktop app build failing due to missing OAuth client IDs at runtime
• Added GOOGLE_CLIENT_ID and GH_CLIENT_ID to the vite define block for main process
• These are now baked into the bundle at build time instead of read from process.env at runtime

Test plan

• Trigger desktop build workflow on this branch
• Download and test the auth flow

🤖 Generated with Claude Code

Summary by CodeRabbit

• New Features
  • Desktop app now supports Google and GitHub sign-in.
  • Build-time configurable API/web endpoints and OAuth client IDs, allowing the desktop app to be pointed to custom backends and enable third‑party authentication.

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