[FEAT] Add Plugin cleanup support when BpmnVisualization is disposed

[tbouffard]

Is your feature request related to a problem? Please describe.

Plugins in bpmn-visualization-addons can register event listeners, allocate objects, keep internal references, or start timers.
Since the core library now provides a dispose() method on BpmnVisualization (see process-analytics/bpmn-visualization-js#3415), the core instance can clean up resources, but plugins still cannot.
This may create memory leaks in long-running applications or SPA environments.

Describe the solution you'd like

Add a new plugin lifecycle hook to let plugins release their resources when the underlying BpmnVisualization is disposed.

Proposed changes:

• Add a new optional method onDispose(): void on plugins
• Add a new onConfigure(bv) hook for consistency (as onDispose), while keeping configure(bv) for backward compatibility
• During disposal, the addons wrapper should:
  • call plugin.onDispose?.()
  • then call bpmnVisualization.dispose()

Example API:

export interface Plugin {
  readonly id: string;

  onConfigure?(bv: BpmnVisualization): void;
  onDispose?(): void;

  // backward compatibility, probably to replace by only keeping onConfigure
  configure?(bv: BpmnVisualization): void;
}

Describe alternatives you've considered

• Using only configure and not adding onDispose, but this leaves plugins without a cleanup mechanism.
• Naming the method dispose(), but this can be confusing because the core object already has its own dispose().
  onDispose makes it clear that it is a lifecycle hook.

Additional context

This hook will help plugin authors properly clean up:

• DOM or graph event listeners
• timers or intervals
• references to the BpmnVisualization instance
• cached data or internal state

It also aligns plugin lifecycle management with the new disposal capabilities introduced in the core library.