v0.151.0: Branded macOS installer with MCP and session reliability fixes

New features

- Skill slash commands in editors - Skill slash commands are now available when connecting from external editors

Improvements

- macOS installer branding - The macOS DMG installer is now branded (app)
- MCP results as markdown - MCP tool results returned as JSON now render as formatted markdown

Bug fixes

- Session reconnection - Sessions now stay rendered and reconnect instead of redirecting to a Session Unavailable page (app)
- Org switcher - The desktop organization switcher now shows the currently selected organization (app)
- Desktop MCP sign-in - Improved desktop MCP authentication callback handling (app)
- Composer actions layout - Composer actions now stay on a single line (app)