Export .dat recordings to individual JSON files

[pavithra-suresh]

ULYP recordings are stored as binary .dat files, which are:

• Not human-readable
• Hard to diff or review
• Teams need an easy way to Inspect recordings without specialized tooling
• Convert call flows into Mermaid diagrams for docs
• Run automated analysis (stats, searches, flaky test triage)

Impact
Slows down debugging and collaboration
Limits automation (no simple format to parse)
Makes sharing/archiving recordings unmanageable

Goal
Provide a way to convert every recording contained in a .dat file into individual JSON files on disk, with a predictable structure suitable for:

• Mermaid sequence/class diagram generation
• Text diffs and code reviews
• Programmatic analysis
• Long-term archival in a human- and machine-readable format

Acceptance Criteria
Given an input .dat, the exporter writes one JSON per recording/root to a target directory
JSON is pretty-printed with stable key order
Handles large recordings without excessive memory usage
Exit codes and clear error messages for invalid inputs/paths

(Optional) A manifest.json summarizing exported files (ids, roots, durations, threads)
Nice to have (can be separate follow-ups)
Filters (by package/method/thread)
Depth limitDirect Mermaid output

[pavithra-suresh]

Below PR addresses this issue
#191