feat(suite): cap the pre-run payloads kept in a suite

[qu0b]

Implements @skylenet's suggestion: a size limit on pre-run bundles, 512MB default, anything over it skipped.

Why

The jochemnet bloatnet pre-run bundle is a single 9.4 GiB pre-run.request — roughly 8k blocks of setup. CreateSuiteOutput copies it into the suite directory on every job, and the runner then uploads it. Nothing consumes it: the runner replays pre-runs from the fixtures cache, not from the suite, and the UI has no use for a bundle that size.

What it does

A pre-run step over runner.benchmark.tests.max_pre_run_step_size (default 512MB) is recorded in summary.json and not copied, so it never reaches the bucket. 0 disables the limit.

"pre_run_steps": [
  { "og_path": "pre_run/pre-run.request", "size_bytes": 10062313486, "omitted": true }
]

Two details worth flagging for review:

Checked with a stat before the copy, not at upload time. Skipping it at the upload layer would still leave a 9.4 GiB write into RUNNER_TEMP on every job. Doing it here costs neither the write nor the transfer, and keeps the uploader generic — it has no business knowing which files are pre-run steps.

The entry is recorded as omitted, not dropped. The suite stays honest about what the run replayed, and the UI gets something to check before offering the file for viewing — TestFilesList.tsx:147 currently links suites/<hash>/<og_path>/pre_run.request unconditionally, which would 404 for an omitted bundle. That UI guard is a separate change; this PR gives it the flag to read.

Tests

• TestCreateSuiteOutput_OmitsOversizedPreRunSteps — over the limit: no file written, summary records omitted and the true size, test steps unaffected.
• TestCreateSuiteOutput_KeepsPreRunStepsWithinLimit — under the limit and with the limit disabled, the bundle is stored exactly as before.

How this relates to the other PRs

• fix(upload): multipart the suite upload so multi-GB pre-run bundles land #301 (merged) makes the upload of any large file work at all. Still wanted — it is what stops a >5 GiB file failing the whole suite upload, including the summary.json that the UI actually needs — but with this cap the 9.4 GiB path stops being exercised.
• perf(upload): skip suite objects the bucket already holds #302 (skip unchanged objects) is orthogonal: it stops re-sending the ~2.96 GB of fixture payloads on every run, which this PR does not touch. Together the steady-state suite upload goes from ~12.4 GB a run to ~5 MB.
• fix(suite): merge into the stored summary, not just the local one #303 (merge the stored summary) is a different bug and independent of both. Note it also adds a parameter to CreateSuiteOutput, so whichever of fix(suite): merge into the stored summary, not just the local one #303/feat(suite): cap the pre-run payloads kept in a suite #304 merges second needs a trivial rebase — happy to fold both into an options struct if you'd rather.

Verification

make build-core, make lint-core (0 issues), full go test ./pkg/... ./cmd/... all pass locally.

[qu0b]

Both addressed.

Renamed and moved. You're right that the name didn't say what it affects — and under tests it read like a test-execution setting, which made it worse. It's now runner.benchmark.results_upload.max_pre_run_upload_size, sitting next to the rest of the upload config so the path and the name both point at what it governs:

runner:
  benchmark:
    results_upload:
      max_pre_run_upload_size: 512MB

I went with max_* over skip_upload_pre_runs_size to match the existing size options, but it's a one-line change if you prefer yours.

Docs. docs/configuration.md gets the option in the results_upload table plus a Pre-Run Upload Size section covering why the cap exists, what an omitted bundle looks like in summary.json, and that the bytes stay in the fixtures artifact if anyone needs to inspect one. config.example.yaml moved with it.

One other change since you looked: the size check now runs before anything is created, so an omitted bundle leaves no empty pre_run/ directory implying a file that was never stored.