Revamp trigger event catalog

[cytommi]

💸 TL;DR

Adds a developer-oriented catalog for all 20 supported trigger events. It documents delivery behavior, explorable payload types, actor semantics, redaction, and the safety-processing contract while keeping generated API references authoritative for schema details.

📜 Details

Design Doc: N/A
Jira: N/A

• Adds the Trigger Event Catalog to the current and 0.14 documentation
• Adds direct catalog links from the existing Triggers guide and sidebar
• Links request types to generated API schemas and places top-level payload fields in collapsible sections
• Clarifies submit versus create delivery behavior, safety deadlines, and follow-up delete events
• Documents report, delete, moderation, AutoModerator, lifecycle, and app-mention event contracts
• Keeps runtime APIs and generated EventTypes pages unchanged

🧪 Testing Steps / Validation

• yarn build passes
• Catalog links, event anchors, and payload disclosures verified in the browser at desktop and narrow widths
• Both catalog versions contain all 20 supported event keys
• New catalog files pass Prettier
• yarn test:types reports existing unrelated Cannot find namespace 'JSX' errors in shared components

✅ Checks

• CI tests (if present) are passing
• Adheres to code style for repo
• Contributor License Agreement (CLA) completed if not a Reddit employee