fix(ios): TabView navigation fixes and code review cleanup

[datlechin]

Summary

• Fix NavigationStack/TabView architecture: single NavigationStack wrapping TabView instead of per-tab stacks. Resolves toolbar and title not displaying on iPhone.
• Move QueryEditorView run button and menu inline (TabView blocks toolbar propagation)
• Dynamic navigationTitle per tab (Tables/Query show connection name, History/Settings show tab name)
• Cache coordinators in ConnectionListView to preserve state across back/forward navigation
• Load databases/schemas before setting phase to prevent toolbar flicker
• Fix coordinator race condition on mid-connect navigation
• Fix reorderSection sort corruption in grouped connection list
• Localize alert/dialog strings in QueryEditorView and QueryHistoryView
• Cancel pending tasks on view disappear (saveQueryTask, dismissSuccessTask)
• Refresh columnDetails on initial DataBrowserView load
• Add accessibility labels to keyboard shortcut buttons
• Add Sendable conformance to ConnectedTab
• Add systemGroupedBackground to RowDetailView

Test plan

• Connect to a database, verify toolbar (database switcher, schema icon) appears
• Switch between tabs, verify title updates (connection name / History / Settings)
• Query tab: inline Run button visible, tap to execute, ellipsis menu works
• Tables tab: tap a table, DataBrowserView pushes with native animation
• Back to connection list, tap same connection again, connects without issues
• RowDetailView: no white background bleeding behind nav/bottom bars
• Grouped connections: reorder within a group, verify other groups unchanged
• iPad: verify all tabs work with sidebar layout