v0.84.0: Header redesign, Execute tool syntax highlighting, session type tags, and skill execution fixes

New features

- Header redesign - Refreshed CLI header with an updated layout for improved readability
- Execute tool syntax highlighting - Execute tool calls now display with syntax highlighting for better readability
- Session type tags - Sessions now display type tags for Missions and subagents for easier identification
- Usage Limits settings UI - New interface for viewing and managing Usage Limits settings (Factory App)

Improvements

- Create tool display - Improved text wrapping and syntax highlighting for Create tool results
- CLI onboarding - Improved onboarding flow for new CLI users

Bug fixes

- Semantic diff rendering - Fixed a random character appearing at the top of semantic diffs
- Skill execution - Fixed skills not executing properly after being loaded
- Gemini BYOK thinking - Fixed thinking signature preservation for Gemini models with custom API keys