Add a New Webhook Event Handler

Follow these steps exactly. Do not skip any step.

Step 1: Write Failing Tests

Create test file tests/events/<handler-name>.test.ts with test cases for:

• Valid payload parsing
• Invalid payload rejection (returns err)
• Edge cases (system notes, ignored actions)

Run bun test to confirm the tests fail.

Step 2: Add Zod Schema

In src/events/parser.ts:

• Define the Zod schema for the new event payload
• Export the inferred TypeScript type