feat: add Quick Connect widget for iOS

[datlechin]

Summary

• Add WidgetKit Quick Connect widget (small + medium sizes) for iOS Home Screen
• Tap a connection → opens app → auto-connects via deep link (tablepro://connect/{uuid})
• Shared data layer via App Group container (widget-connections.json)
• 10 new widget files, 4 modified app files

Setup required after merge

The widget extension target must be added in Xcode manually:

1. Open TableProMobile.xcodeproj in Xcode
2. File → New → Target → Widget Extension → name: TableProWidget
3. Set bundle ID: com.TablePro.TableProMobile.Widget, deployment target iOS 17.0
4. Delete the auto-generated files (they're already in TableProWidget/)
5. Add existing files from TableProWidget/ to the new target
6. Add Shared/WidgetConnectionItem.swift and Shared/SharedConnectionStore.swift to BOTH targets
7. Enable App Group capability on both targets: group.com.TablePro.TableProMobile
8. Add URL scheme tablepro to main app target (URL Types in Info tab)

Test plan

• Add widget target in Xcode, build both targets
• Verify widget appears in widget gallery
• Add small widget → shows first connection
• Add medium widget → shows up to 4 connections
• Tap widget connection → app opens and navigates to connection
• Test deep link: xcrun simctl openurl booted "tablepro://connect/{uuid}"
• Delete all connections → widget shows empty state
• Add/remove connection → widget updates