feat: add support for instant and parallel event function handlers

[Copilot]

Parallel Event Handler Support

Adding support for instant and parallel event function handlers to CommandKit.

Event handlers can now export parallel = true to execute concurrently using Promise.all(), while handlers without this flag continue to execute sequentially as before.

Changes Made

• EventListener Type: Added parallel boolean field to track parallel execution mode
• Event Loading: Modified loadEvents() to read the parallel export from event handler modules
• Listener Grouping: Separated listeners into parallel and sequential groups for both regular and once-only listeners
• Execution Logic:
  • Parallel listeners execute concurrently using Promise.all()
  • Sequential listeners execute in order (existing behavior)
  • Parallel listeners run before sequential listeners
• Error Handling: Errors in parallel handlers don't stop other parallel handlers from executing
• Logging: Updated event registration logging to show counts of sequential/parallel listeners
• Formatting: Applied prettier formatting to code

Usage

Event handlers can now opt-in to parallel execution:

// File: src/app/events/interactionCreate/handler.js

// Export parallel flag to execute this handler concurrently
export const parallel = true;

export default async function (interaction) {
  // handle event
}

Testing

• ✅ TypeScript compilation passes
• ✅ Build process completes successfully
• ✅ Code formatted with prettier

Fixes #568

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Add support for instant + parallel event function handlers</issue_title>
<issue_description>The current event handler implementation calls event functions in an order, while waiting for the previous one to finish. Some situations require multiple, instant, and parallel handling which the current handler lacks.

Proposed structure

// File: src/app/events/interactionCreate/handler.js

// an export to treat this handler differently from the ones running in sequence
// ckit might use something like Promise.all() to call them all at once
export const parallel = true; // variable name might need work

export default async function (interaction) {
  // handle event
}
```</issue_description>

<agent_instructions>your work goes inside `packages/commandkit/src/app/handlers/AppEventsHandler.ts` file for this issue. Just grab `parallel` export from the loaded event file and group parallel vs sequential and register them with different execution logic.</agent_instructions>

## Comments on the Issue (you are @copilot in this section)

<comments>
</comments>

Fixes #568

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[twlite]

@copilot do not worry about tests, only make the necessary changes and make sure the build passes

[Copilot]

@copilot do not worry about tests, only make the necessary changes and make sure the build passes

Done! I've removed the test file and focused only on the implementation. The build passes successfully. Changes include:

• Added parallel flag to EventListener type
• Read parallel export from event handler modules
• Parallel handlers execute concurrently via Promise.all()
• Sequential handlers execute in order (existing behavior)

Commit: The changes are in the commit above.

[twlite]

@copilot please run pnpm prettier:format from the root and push the changes

[Copilot]

@copilot please run pnpm prettier:format from the root and push the changes

Done! Ran pnpm prettier:format and pushed the formatting changes. Commit: 79953af (formatting applied)