moving from wpf to avalonia to make this crossplatform, linux first

[Ashfaaq18]

fix #100

WPF -> Avalonia Parity Checklist (Feature-Based)

1) App Structure / Core Migration

• Avalonia project added and buildable alongside WPF.
• Platform abstractions project in place (INetworkCaptureService, IProcessIconService, etc.).
• Core/shared VM extraction started (OpenNetMeter.Core).
• Avalonia main window shell with Summary / History / Settings tabs.

2) Summary Tab Parity

• Summary layout ported.
• Live graph rendering wired.
• Active processes list wired.
• Active process sorting wired.
• Footer download/upload speed display wired to settings format.

3) History Tab Parity

• History layout ported.
• Profile/date filtering wired.
• Production DB read path wired.
• Totals calculation wired.
• Sorting wired.
• History process icon binding wired.

4) Settings Tab Parity (UI vs Behavior)

• Settings UI mostly present.
• Settings JSON persistence wired for core fields.
• Network target + speed unit/magnitude values persist.
• Start-with-Windows behavior parity missing (OS startup registration not wired in Avalonia).
• Minimize-on-start behavior parity missing (currently persistence-level only).
• Reset data behavior parity missing (currently placeholder).
• Update check behavior parity missing (currently placeholder).
• Download update behavior parity missing (currently placeholder).
• Dark mode runtime behavior parity incomplete (setting exists; full runtime theme switching parity pending).
• Mini-widget-related settings behavior parity missing (visibility/transparency currently not backed by a real mini-widget window).

5) Mini Widget Parity (Major Gap)

• Avalonia mini widget window not implemented.
• Always-on-top/pinned widget behavior not implemented.
• Widget show/hide flow not implemented.
• Widget position persistence not implemented.
• Widget transparency/background sync not implemented.
• Widget live metric binding parity not implemented.

6) Windowing / Secondary Windows Parity

• About window implemented.
• Confirmation dialog parity missing (WPF reset confirmation flow not ported as real dialog window).
• Custom title bar and window controls implemented.

7) Tray / Lifecycle Parity

• System tray icon/menu parity missing.
• Tray-based hide/show/minimize flows missing.
• WPF-style startup/minimized-to-tray lifecycle parity missing.

8) Platform Service Parity

• Windows network capture service wired for Avalonia.
• Placeholder network capture service for non-Windows.
• Windows process icon service wired.
• Placeholder process icon service for non-Windows.
• Linux real capture backend not implemented.
• macOS real capture backend not implemented.
• Linux/mac startup registration backends not implemented.
• Linux/mac tray/mini-widget equivalents not implemented.

9) Logging / Diagnostics

• Event logger upgraded in Avalonia (WPF-style API + app lifecycle hooks).
• Catch blocks instrumented with logging.
• Windows-only callsites properly marked (CA1416 warnings resolved without suppression).

10) Release / CI / Docs Parity

• Linux publish path/script exists.
• Avalonia CI workflow parity not finalized.
• README/user-facing Avalonia guidance not finalized.
• Installer/release parity with WPF distribution not finalized.

as of commit 27506fc
this has a minimal buildable, runnable windows and Linux binary

as of commit f306775

as of commit 122b0a0