8b2ae957e5
Refactor retry signal detection to be provider-agnostic: - Replace hardcoded Copilot/OpenAI checks with generic pattern matching - Detect any provider message containing limit/quota keywords + [retrying in X] - Add OpenAI pattern: 'usage limit has been reached [retrying in X]' - Update logging to use generic 'provider' instead of specific names - Add 'usage limit has been reached' to RETRYABLE_ERROR_PATTERNS This enables fallback escalation for any provider that signals automatic retries due to quota/rate limits, not just Copilot and OpenAI. Closes PR discussion: generalize retry pattern detection