feat(evolve-kernel): per-iteration progress table in detail page

[6eanut]

The metric cards only surface the last iteration's speedup and the library's current best, so a run that is stuck — or that regressed after a good iteration — looks identical to one that is climbing, and the per-iteration "goal" (what the optimizer set out to do) was not visible anywhere.

Add an "Iteration Progress" panel rendered from the already-fetched /iterations payload: one row per iteration with status, exec time, speedup, library size, duration and goal. Rows that set a new best exec time are marked green with a "▲" tag — the "is it actually improving?" signal.

• export formatMs from ok-kernel-library.js so both tables share one formatter instead of duplicating it
• coerce perf.speedup with Number() before toFixed: the value is stored straight from an LLM-generated perf harness report with no numeric validation, so a malformed row now degrades to "—" instead of throwing
• add tests/test_iteration_progress.py pinning the reader fields the table renders, plus that a partially written iteration record does not take the whole list down