Feature: Auto debug logging when running in Debug + shared test-logging library + debug panel

[boexler]

Summary

When developing the NLogViewer app, it would be helpful if:

1. Auto test logging in Debug – When the application is started in Debug (e.g. F5), the same behavior as the current Sentinel.NLogViewer.App.TestApp runs automatically: generate sample log messages and send them via UDP so the viewer can display them without manually starting the separate TestApp.

2. Shared test-logging logic – The logic currently in the TestApp (NLog target switching, timer-based log generation, random messages, exception generation) should be moved into a common/shared project so that:

   • The console TestApp becomes a thin wrapper that uses this library.
   • The main WPF app can use the same library when running in Debug.

3. Debug panel – A debug-only panel in the main application where the user can:

   • Decide whether to create a new instance of the test log generator (with specific parameters).
   • Configure parameters (e.g. NLog target: chainsaw/log4jxml, UDP host/port, message interval, exception probability) to test logging.

Current state

• Sentinel.NLogViewer.App.TestApp is a separate console app that:
  • Updates NLog target via NLOG_TARGET (chainsaw / log4jxml).
  • Runs a timer that generates random log messages and exceptions (20% chance) and sends them to UDP (e.g. 127.0.0.1:4000).
• The main app Sentinel.NLogViewer.App has no built-in way to generate test logs; developers must run the TestApp separately.

Proposed approach

• New project (e.g. Sentinel.NLogViewer.Debug or Sentinel.NLogViewer.TestLogging):
  • Contains: NLog target switching, log message generator (random levels, messages, logger names, exception injection), configurable interval and parameters.
  • Can be referenced by both the TestApp and the main App.
• Main app (Debug only):
  • On startup in Debug: optionally auto-start the test log generator (e.g. with default parameters matching current TestApp).
  • Debug panel: UI (e.g. collapsible panel or menu item "Debug → Test logging") to start/stop a generator instance and set parameters (target, host, port, interval, exception chance).
• TestApp: Refactor to use the shared project; keep only console entry point and "press key to stop" behavior.

Acceptance criteria

• Test log generation logic lives in a shared project; TestApp uses it.
• When the main app is run in Debug, test logging can run automatically (configurable).
• Debug panel allows starting/stopping a test log generator and configuring parameters (target, UDP host/port, interval, exception probability).
• No functional change to Release builds; debug features are conditional (e.g. #if DEBUG or runtime check).