Handle existing PHP binary CDN builds

[bcotrim]

Related issues

• N/A

How AI was used in this PR

Codex assisted with the implementation, fixture checks, and PR summary. I reviewed the diff and verification output.

Proposed Changes

• Allow PHP CLI binary Apps CDN uploads to update an existing build instead of failing on duplicate versions.
• Add a post-upload metadata generator that writes CDN URL and SHA data to tools/common/lib/php-binary-cdn-metadata.json.
• Open an automated metadata PR after successful CDN uploads when the generated JSON changes.
• Keep one tracked patch version per PHP minor version, skipping older patch uploads when a newer patch is already recorded.
• Document the duplicate-upload and metadata PR behavior.

Testing Instructions

Optional end-to-end workflow test

1. Go to Actions → Build PHP CLI Binaries → Run workflow.
2. Select branch: handle-php-binary-existing-versions.
3. Use inputs:
   • php_version: a real patch version to upload, e.g. 8.4.21
   • spc_ref: 2.8.5
   • debug: false
   • upload_to_apps_cdn: true
   • apps_cdn_visibility: internal
4. Wait for the build matrix and Publish Apps CDN artifacts job to finish.
5. Verify the workflow summary says the PHP CLI artifacts were uploaded or updated.
6. Verify a new branch named update-php-cli-metadata-<version>-<run_id> was pushed.
7. Verify a PR was opened against handle-php-binary-existing-versions.
8. Verify that PR only updates tools/common/lib/php-binary-cdn-metadata.json with the CDN URLs and SHA-256 hashes.

Pre-merge Checklist

• Have you checked for TypeScript, React or other console errors?

[wpmobilebot]

📊 Performance Test Results

Comparing 7455c52 vs trunk

app-size

Metric	trunk	7455c52	Diff	Change
App Size (Mac)	1354.53 MB	1354.53 MB	+0.00 MB	⚪ 0.0%

site-editor

Metric	trunk	7455c52	Diff	Change
load	1490 ms	1521 ms	+31 ms	⚪ 0.0%

site-startup

Metric	trunk	7455c52	Diff	Change
siteCreation	8579 ms	8569 ms	10 ms	⚪ 0.0%
siteStartup	4940 ms	4929 ms	11 ms	⚪ 0.0%

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Results are median values from multiple test runs.

Legend: 🟢 Improvement (faster) | 🔴 Regression (slower) | ⚪ No change (<50ms diff)