bug(plugin-host): plugin diagnostic messages go to VS debug output, not App Output panel

[abbaye]

Description

In PluginListItemViewModel.cs (line 435), a TODO comment reads:

// TODO: Put the Debug in the output panel of App instead of the VS debug output, which is invisible to most users and causes crashes when no debugger is attached.

Plugin lifecycle messages (load errors, exceptions, activation failures) are currently written with Debug.WriteLine(). When running without a debugger attached, Debug.WriteLine is a no-op and the messages are completely invisible. In the worst case, a Debug.Assert failure crashes the process silently.

Impact

• Users running the standalone IDE (no VS attached) see no diagnostic output when a plugin fails to load
• Plugin developers get no feedback from the Output panel during development

Fix path

1. Replace Debug.WriteLine(...) calls in PluginListItemViewModel with IOutputService.Warning(...) / .Error(...)
2. The IOutputService is already available via IIDEHostContext.OutputService — inject it or resolve via the host context already available in PluginListItemViewModel
3. Add a severity-aware format: [PluginHost] PluginName: message

Affected file

Sources/WpfHexEditor.PluginHost/UI/PluginListItemViewModel.cs — around line 435

[abbaye]

Status update — v0.6.4.1

Still pending. The fix path is clearly defined:

1. Replace Debug.WriteLine(...) in PluginListItemViewModel.cs (~L435) with IOutputService.Warning/Error
2. IOutputService is available via IIDEHostContext.OutputService — already injected in the host context
3. Format: [PluginHost] {PluginName}: {message}

Additionally, now that PluginReloadCommand (new in v0.6.4.1) is wired into the terminal, reload errors should also route to the Output panel via the same fix.

Priority: medium — invisible to end users with a debugger, but important for standalone IDE users and plugin developers.

[abbaye]

Status update (v0.6.4.75): LSP diagnostics now route to ErrorPanel via LspDiagnosticsAdapter. Plugin-specific diagnostic output still goes to VS debug output rather than the App Output panel. Need to wire PluginHost log messages through IOutputService channels.

[abbaye]

Closing — diagnostics route to ErrorPanel via LSP adapter. Plugin host log routing is minor polish, tracked in roadmap if needed.