Add daily API tracking between local and upstream JSON APIs

[simbo1905]

Feature Request

Track API differences between our local jdk.sandbox.java.util.json backport and the upstream OpenJDK java.util.json API on a daily basis.

Requirements

1. Daily automated check via GitHub Actions
2. Compare public APIs between local and upstream implementations
3. Report any differences found
4. Use compiler parsing for accurate API extraction

Implementation

• API tracker module that uses reflection for local classes and compiler parsing for upstream sources
• GitHub Action running daily via cron schedule
• Output report showing API differences

This will help us stay synchronized with upstream API changes.

[simbo1905]

On this we will dog-food our own back port.