refactor(winui): replace DevWinUI with native controls

[mchave3]

Summary

Replace the DevWinUI dependency with native WinUI 3 controls and app-owned services.

Reason

DevWinUI increased the packaged application size and owned shell behavior that can be implemented directly with WinUI 3.

Main changes

• replace DevWinUI navigation and breadcrumbs with a native NavigationView, Frame, and BreadcrumbBar service
• rebuild the Home page with native WinUI 3 controls
• replace DevWinUI theme, application metadata, package identity, and startup helpers
• remove the Explorer context-menu integration and obsolete DevWinUI resources, generated mappings, packages, and manifest entries
• retain localized navigation content and runtime language refresh

Testing

• x64 solution build: passed
• ARM64 solution build: passed
• x64 tests: 1,141 passed
• ARM64 tests: not executed locally because the x64 host cannot run the ARM64 test host
• x64 and ARM64 Velopack/MSI packaging: passed
• packaged x64 UI smoke test: Home, navigation routes, Settings, and native settings pages rendered successfully
• format check: 44/44 XAML files passed; no source files required formatting
• final read-only review: no findings

Package size

Artifact	x64	ARM64
Publish directory	268,062,708 -> 205,069,970 bytes (-23.5%)	287,030,741 -> 215,929,973 bytes (-24.8%)
Full package	104,811,142 -> 79,616,190 bytes (-24.0%)	101,487,206 -> 77,328,650 bytes (-23.8%)
MSI	90,651,997 -> 69,370,505 bytes (-23.5%)	86,047,675 -> 66,232,551 bytes (-23.0%)

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