RouterChat for OpenRouter

- Refreshed chat interface: Switch models, manage attachments, and reach chat controls from the redesigned composer. - Automatic chat titles: Name new chats automatically, or generate and edit a title yourself. - Organized conversation branches: See new branches nested beneath their parent chats in history. - Richer answers: Read formatted math, syntax-highlighted code, and Mermaid diagrams, with improved Markdown across languages. - Expanded OpenRouter tools: Configure supported search engines, helper models, filters, and tool limits. Inspect reported tool activity and source excerpts. - Voice improvements: Optional TTS chunking lets Hands-free start speaking before the full answer arrives, alongside improved interruption recovery and saved-audio playback. - Easier settings and improved reliability: Reorganized feature settings, more efficient library preparation, and fixes throughout chat and media generation.