v0.9.0

• Replace Apple Mail and Calendar integrations with Google OAuth2
• Add Google account connection in Settings tab (OAuth2 with PKCE, browser-based flow)
• Calendar tab now shows Google Calendar events (next 14 days)
• Gmail Suggestions tab polls unread Gmail for actionable emails via AI filtering
• CLI suggestions commands now use Gmail instead of Apple Mail
• Cross-platform: no longer requires macOS (removed osascript dependency)

Full Changelog: v0.8.13...v0.9.0