What's new

Full GitHub PR integration with review threads, status checks, and merge from the app. Plus a complete UI refresh with Orkest branding.

• Added GitHub PR status card with checks, review decision, and merge button
• Added PR review threads viewer with markdown rendering and inline comments
• Added one-click PR merge with optimistic state updates
• Redesigned UI with Orkest brand colors and Inter font
• Added Changes tab with diff viewer, PR status, and review comments
• Added GitHub Issues integration in chat input
• Moved Agents management to Settings for a cleaner sidebar
• Improved PR detection to always show the correct active PR
• Fixed changelog links to open version-specific detail pages