v2.5.3
Fix CPU spikes (99% → <5%) + Add OpenRouter provider
Performance:
- Replace VStack with LazyVStack in ChatView — only renders on-screen messages
- Add Equatable to MessageBubbleView — skips Markdown re-parse when unchanged
- Root cause: every keystroke triggered O(N) Markdown AST rebuilds across all messages
OpenRouter Integration:
- Add OpenRouter as first-class provider (openrouter.ai/api/v1)
- 10 curated models: GPT-5.2, Claude Sonnet 4, Gemini 2.5 Pro, DeepSeek R1, etc.
- OpenRouter-specific headers (HTTP-Referer, X-OpenRouter-Title)
- Full onboarding flow with setup instructions"