- Add ProviderOptionsSection component for per-provider thinking_mode and context_1m
- Store options in options_json column (DB providers) or settings table (env provider)
- Add /api/providers/options GET/PUT route
- Fix SDK integration: use `betas` (not `betaHeaders`) for context-1m-2025-08-07
- ChatView and /chat page always reset thinkingMode on provider change (isolation fix)
- Auto-correct model when switching providers if model not in new provider's list
- Add i18n keys for provider options in both en.ts and zh.ts
- Update test fixtures with options_json field
- Remove unused lastAssistantText variable in claude-client.ts
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
