fix(react): cache event handler references for proper cleanup (#1235)

[armorbreak001]

Problem

Fixes #1235

Event listeners registered via pm.on() are never properly removed by pm.off() because each call to setupEventListeners() creates new function references.

Root Cause

// BEFORE (broken):
private handler(eventName: string) {
  return (data: unknown) => {   // ← new function every call!
    this.props.onPluginEvent!(eventName, data);
  };
}

// setupEventListeners calls: pm.on('event', this.handler('event')) → fn#1
// cleanupEventListeners calls: pm.off('event', this.handler('event')) → fn#2
// fn#2 !== fn#1, so pm.off() cannot find and remove the listener

Impact

• Duplicate events: Every component re-render adds more listeners
• Memory leak: Old listeners are never garbage collected
• pm.off() is a no-op: Cleanup code appears to work but does nothing

Fix

Cache handler functions in a Map<string, Function> so the same reference is always used:

// AFTER (fixed):
private readonly eventHandlers = new Map<string, (data: unknown) => void>();

private getEventHandler(eventName: string): (data: unknown) => void {
  if (!this.eventHandlers.has(eventName)) {
    this.eventHandlers.set(eventName, (data: unknown) => {
      this.props.onPluginEvent!(eventName, data);
    });
  }
  return this.eventHandlers.get(eventName)!;
}

Now pm.on(event, getEventHandler(event)) and pm.off(event, getEventHandler(event)) receive identical function references.

Testing

• ✅ All 177 unit tests pass
• ✅ No behavior change — same events fired with same data
• ✅ Handlers cached per event name for component lifetime

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud