benchmark: replace simulation with walltime macro benches + e2e correctness

[natemoo-re]

Our CodSpeed benchmarks were frequently inaccurate: they flagged big "regressions"/"improvements" on PRs that don't touch the measured code (a test-file rename alone showed −54% on input; "dashboard layout" swung 20×). And the simulation job's runtime was wildly unpredictable.

• Both problems are baked into CodSpeed's Valgrind simulation of tiny (µs) benchmarks, confirmed by their own docs, and chasing them one bench at a time is whack-a-mole.
• This PR drops the simulation job entirely and moves all perf gating to WallTime macro benchmarks: bigger, realistic workloads where the real work dominates and noise averages out (stable to <1%, predictable runtime).
• Replacements:
  • input parsing → an event-loop correctness test + a throughput benchmark;
  • render/ops → WallTime macro benches (render dashboard frames, pack complex layouts).
• Also pinned the CI build (fixed compiler, no stale wasm cache) so the baseline can't silently drift.
• Net: green CI actually means green — no phantom red/green on unrelated PRs.

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/clayterm@91

commit: da52f33

[codspeed-hq]

Merging this PR will not alter performance

✅ 5 untouched benchmarks
🆕 5 new benchmarks
⏩ 18 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
🆕	WallTime	input throughput (mixed corpus, chunked read loop)	N/A	9.5 ms	N/A
🆕	WallTime	pack complex layout	N/A	46.5 ms	N/A
🆕	WallTime	pack large list	N/A	60.4 ms	N/A
🆕	WallTime	render mixed frames	N/A	36.8 ms	N/A
🆕	WallTime	render steady diff	N/A	35.6 ms	N/A

---

_{Comparing ci-bench (da52f33) with main (be7e746)}

Footnotes

1. 18 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[jbolda]

The change to walltime makes sense. We were just discussing this aspect of codspeed on Thursday for some effection code. Might be worth just generally writing down the whys and whats for some of the decisions we made though!