Feature Request: Auto-fallback to Gemini Flash on rate limit

[nithish-95]

Current Behavior:
When using Gemini Code Agent in Zed, if Gemini 2.5 Pro hits rate limits or runs out of tokens, the agent stops working.

Expected Behavior:
Zed should automatically detect when Gemini Pro is rate-limited and fall back to Gemini Flash to maintain an uninterrupted workflow.

Proposed Solution:

• Detect rate limit/quota errors from Gemini API
• Automatically retry the request with the Gemini Flash model
• Optionally: notify user that fallback occurred
• Optionally: allow configuration of fallback model preference

Use Case:
Developers frequently hit Gemini Pro token limits during heavy coding sessions. Automatic fallback would prevent workflow interruptions.

Environment:

• Zed version: Zed 0.209.6
• OS: Mac OS 26.0.1