perf: establish BrowserPod cold, warm, and persistent-install baselines

[yhay81]

Context

The published 57.1-second / 880 MB measurements belong to the removed WebContainer path and must not guide BrowserPod optimization. The adopted provider currently has no owner-authorized performance record.

Scope

Measure the exact BrowserPod 2.12.1 install and Gateway-ready path without changing behavior first. Treat metering, persistence, and transfer/storage cost as part of the result.

Acceptance criteria

• bind every measurement to the exact browser/OS, BrowserPod version, OpenClaw version, and npm integrity;
• capture cold install, warm install, persistent-storage reuse, Gateway-ready latency, installed bytes, cache/storage bytes, and failure/timeout behavior;
• separate provider boot/delivery time, npm install time, Gateway start time, and health/handshake time;
• run at least three samples per path and report median plus individual samples;
• verify that persistence invalidates on OpenClaw version or integrity change;
• redact credentials, tokens, portal identifiers where sensitive, and user payloads;
• add regression budgets only after evidence exists; do not carry forward WebContainer thresholds;
• run the normal report validation and affected browser evidence lane.

[yhay81]

Harness update: PR #52 adds the measurement harness for this issue on the hello-agent reference chain — the path the strategy doc marked "executable independent of the vendor gaps" after the first runtime record (#48).

What it covers today:

• cold / warm / persistentReuse passes, six phase timings per sampled boot (embed boot, provider boot from the runtime boot audit, digest-verified staging, readiness, first round trip, cooperative close), storage estimates, median + raw samples, and the ≥3-samples publishable floor as a meetsSampleFloor flag.
• payload-free schema with a digest-bound record; exact identity binding to the fixture artifact + provider version + browser + OS.

What stays open on this issue until #6/#47 close: OpenClaw npm-install time, installed bytes, and Gateway-start/health separation on the real upstream artifact. Persistence invalidation on version/integrity change is structural (per-artifact storage keys), noted in the README section.

Next step is owner-authorized and metered: node examples/hello-agent-evidence-host/perf-capture.mjs --samples 3 ≈ 10 boots for a publishable baseline, or --samples 1 ≈ 4 boots for a first exploratory run. The driver prints the exact planned cost before the first spend.

[yhay81]

First owner-authorized baseline captured (2026-07-21, browserpod@2.12.1, HeadlessChrome 149, Windows 11) with the merged harness — three samples per pass, 10 metered boots total. Checked in with its digest-bound record in PR #53.

pass	provider boot (median)	staging	readiness	first round trip	close
cold	844 ms	12 ms	5117 ms	163 ms	123 ms
warm	690 ms	7 ms	5397 ms	156 ms	109 ms
persistentReuse	792 ms	8 ms	3687 ms	164 ms	62 ms

≈6.2 s cold / ≈4.7 s persistent-reuse to the first protocol round trip; ≈1.75 MB reported storage growth per fresh workspace; every pass meets the ≥3-sample floor. Notable: persistentReuse readiness trended down across consecutive samples (4533 → 3687 → 2810 ms).

Still open on this issue (vendor-blocked, #6/#47): OpenClaw npm-install time, installed bytes, and Gateway-ready/health separation on the real upstream artifact. Regression budgets stay deferred per the acceptance criteria — this is the first evidence, not a threshold.