fix(frontend): implement safe event listener to prevent handlerId crashes and frontend refreshes

[Copilot]

SJMCL was experiencing crashes with the error "Cannot read properties of undefined (reading 'handlerId')" followed by automatic frontend refreshes after extended use. This issue was particularly problematic during task management, instance operations, and other background processes that rely heavily on event listeners.

Root Cause

The issue was caused by unsafe cleanup of Tauri event listeners throughout the application. The problematic pattern looked like this:

// PROBLEMATIC - can cause crashes when context is destroyed
static onProgressiveTaskUpdate(callback: (payload: PTaskEventPayload) => void): () => void {
  const unlisten = getCurrentWebview().listen<PTaskEventPayload>("task:progress-update", callback);
  
  return () => {
    unlisten.then((f) => f()); // ❌ This fails when webview context is destroyed
  };
}

When React components unmounted or the webview context was destroyed during navigation, calling unlisten.then((f) => f()) would attempt to access a handlerId property on an undefined object, causing the application to crash and automatically refresh.

Solution

Created a comprehensive safe event listener utility that wraps all Tauri event operations in proper error handling:

// SAFE - handles errors gracefully
static onProgressiveTaskUpdate(callback: (payload: PTaskEventPayload) => void): () => void {
  return createSafeEventListener<PTaskEventPayload>("task:progress-update", callback);
}

Key Components

Safe Event Listener Utility (src/utils/safe-event-listener.ts):

• safeEventListen() - Async wrapper with comprehensive error handling
• createSafeEventListener() - Drop-in replacement maintaining API compatibility
• cleanupListeners() - Safe cleanup for multiple listeners
• All functions include try-catch blocks preventing crashes during cleanup

Services Fixed

Updated all affected services to use the safe event listener pattern:

• TaskService: Fixed 2 critical event listeners (task:progress-update, task:group-update)
• LaunchService: Fixed game process output listener (launch:game-process-output)
• ConfigService: Fixed config update listener (config:partial-update)
• ResourceService: Fixed resource refresh listener (instance:refresh-resource-list)

Benefits

• ✅ Eliminates frontend crashes and unexpected refreshes
• ✅ Prevents memory leaks from uncleaned event listeners
• ✅ Maintains full backward compatibility with existing APIs
• ✅ Adds defensive error handling throughout the event system
• ✅ Safe to call cleanup functions multiple times (idempotent)
• ✅ Includes debug logging that doesn't crash the application

This fix specifically addresses the user-reported issue where SJMCL would crash and refresh after being used for extended periods, especially during intensive operations involving task management and background processes.

Fixes #667.

Warning

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• registry.npmmirror.com
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