Optimize webhooks JSON with compact structure and string interning

[ericsciple]

Overview

This PR optimizes the webhook payload JSON files used for GitHub Actions autocompletion and hover documentation, achieving a 55% size reduction for these files:

Metric	Before	After	Reduction
Minified	464 KB	209 KB	55%
Gzipped	63 KB	22 KB	65%

Changes

New Optimizations

1. Compact array format — Params converted from verbose objects to type-dispatched arrays:

   // Before
   {"name": "issue", "description": "The issue itself.", "childParamsGroups": [...]}
   
   // After  
   ["issue", "The issue itself.", [...]]

2. Object deduplication — Shared structures extracted to objects.json and referenced by index

3. String interning — 414 duplicate property names stored in strings.json and referenced by index

Size Reduction

File	Before	After	Gzip
webhooks	265 KB	141 KB	13 KB
objects	199 KB	62 KB	7 KB
strings	—	6 KB	2 KB
Total	464 KB	209 KB	22 KB

Testing

• All 395 existing tests pass
• Added validation test that compares optimized output against full source (webhooks.full.json) to ensure no data loss
• Lint and format checks pass

Documentation

Updated docs/json-data-files.md with:

• Compact format specification
• String interning explanation
• Deduplication details
• Size reduction breakdown

[ericsciple]

Since the test is normally skipped when the full webhooks file doesn't exist, I made the test write a marker file. With the marker file, we can be sure the test actually ran.

The full webhooks file (unoptimized) is written above by the script npm run update-webhooks

[ericsciple]

I added this job to validate the optimized webhooks JSON is equivalent to the full webhooks JSON file.

Refer changes to the file eventPayloads.test.ts in this PR

[ericsciple]

I renamed this file to update-webhooks.ts but there were also significant updates anyway

[ericsciple]

eventsPayloads.ts reads the compact webhook JSON files which contains the keys and descriptions for each GitHub event payload. This information is used to validate github.event.* syntax and provide descriptions on hover.

A unit test that runs during CI validates the compact webhook JSON files are parsed into a form that exactly matches the full unoptimized webhooks JSON.

The script update-webhooks.ts downloads the full webhook JSON from the GitHub REST API description repository:

import schemaImport from "rest-api-description/descriptions/api.github.com/dereferenced/api.github.com.deref.json";