TT3: Rulial diff / worldline compare MVP

[flyingrobots]

Context

• Once runs are deterministic and history is digest-pinned, the next high-leverage tool is "compare two runs" (first divergence, per-tick diffs).

Goal

• Build a minimal worldline compare tool: side-by-side scrubber + per-tick delta view + jump to first divergence.

Scope

• Define an export format (or reuse existing logs) that includes tick ids, patch digests, admission digests, and key receipts.
• Implement diff alignment + first divergence detection.
• Create a thin UI prototype that renders the comparison.

Exit Criteria

• Two runs can be compared deterministically and the tool can explain divergence sites.

Links

• docs/spec-timecube.md
• docs/spec-time-streams-and-wormholes.md