feat: pre-request token validation, mid-stream error handling, and usage stats improvements
- Qoder: handle mid-stream errors by returning proper error Response instead of embedding in stream
- Qoder: add refreshCredentials() to validate token via quota endpoint before requests
- chatCore: validate and refresh provider tokens before sending chat requests
- chatCore: bail early with 401 on unrecoverable token refresh errors
- Usage stats: track apiKey, comboName, fallbackHistory in request details
- Dashboard: improve Combos, Endpoint, Provider, Usage, and RequestDetails pages
- API keys route: upsert logic with provider_type support
- DB repos: usageRepo query improvements, requestDetailsRepo pagination, apiKeysRepo updates
luulam
2305e26e25