v0.preview.54

v0.preview.54 - 2026-07-06

• Add OpenRouter web search request support and forward top_k in OpenAI-compatible requests
• Update built-in model catalogs
• Fix multibyte truncation in approval previews
• Improve settings and credential storage reliability with race-safe ownership and centralized atomic writes
• Scope permission grants at the permission layer for clearer approval behavior
• Polish TUI sent-message and composer cursor rendering
• Clean up the external protocol shape by removing non-wire behavior and decoupling internal storage/logging details