feat: Quick Connect widget + iOS polish

[datlechin]

Summary

• Quick Connect Home Screen widget (small + medium) — tap to open app and connect
• Deep linking via tablepro://connect/{uuid} URL scheme
• App Group shared data layer for widget-app communication
• SQLite file picker fix (dual fileImporter conflict)
• 6 code quality fixes: force unwrap, batch reorder, SSH credential loading, color picker scroll, toolbar consistency, widget data sync
• Vietnamese translations for all new strings
• Build number bumped to 4

Test plan

• Add small widget — shows first connection
• Add medium widget — shows up to 4 connections
• Tap widget connection — app opens and navigates to that connection
• Add/remove connection — widget updates
• SQLite: Open Database File button works
• Group reorder works without lag
• Color picker scrolls on small screens
• SSH credentials persist when toggling SSH on/off in edit form