Preserve the Engine host module closure in the packed browser gate

Product outcome

Make the adapter's existing fresh packed-browser consumer exercise the published Engine host exactly as a deployable browser bundle. The built consumer must serve prepared-control.js beside the raw Engine AudioWorklet host so its relative import resolves in Chromium.

Bounded implementation

Change only scripts/browser-packed.mjs, this numbered issue spec, and a focused harness test only if the implementation cannot be directly proved by the existing browser gate. Preserve adapter and Engine package/runtime sources, public APIs, package identities, release workflow, and issue #117.

The harness may emit or copy the installed Engine host closure into its temporary Vite output. It must retain the Engine host and worklet asset observations and fail if the required relative companion is absent.

Objective gates

From synchronized adapter main 1a97a7e2a5c8747996388fdf412d82e32156fa15, reproduce the ordinary packed Chromium failure before the correction. Then prove npm run test:browser, the indexed-sparse Chromium gate, npm run check, and package/dry-run gates pass. Confirm no generated evidence or dependencies remain untracked. Record exact commands and outcomes below.

Workflow

One bounded Sol implementation round owns this harness-only correction. Root owns checkpoint commit, push, PR, CI, merge, and any release integration. No publication or change to issue #117 is authorized here.

Evidence

Starting source is clean synchronized adapter main 1a97a7e2a5c8747996388fdf412d82e32156fa15 in isolated worktree /tmp/miso-adapter-packed-closure. The primary checkout and /tmp/miso-adapter-0511-release are untouched.

Bounded implementation and local acceptance

Baseline CHROME_EXECUTABLE=/home/bl/.cache/ms-playwright/chromium-1243/chrome-linux64/chrome npm run test:browser reproduced the defect on Chromium 153.0.8010.12: Vite emitted the raw host at a hashed asset URL, the host requested its relative /assets/prepared-control.js, that request returned 404, and session open failed with Engine host module could not load.

The harness now writes a temporary consumer Vite config that derives a content-addressed directory from the installed SDK asset manifest, emits the host module and ABI layout there under their original filenames, and emits the installed prepared-control.js beside them. The ordinary browser lane explicitly requires requests for both relative companions. No adapter/Engine runtime source, public API, package identity, release workflow, or issue #117 changed.

Local acceptance on Node 22.23.2, npm 10.9.8, and Chromium 153.0.8010.12:

• npm ci --ignore-scripts: PASS, 31 packages, zero vulnerabilities.
• CHROME_EXECUTABLE=/home/bl/.cache/ms-playwright/chromium-1243/chrome-linux64/chrome npm run test:browser: PASS, full packed playback/control/seek/fault assertions, 15 observed JS/Wasm assets, zero request failures and zero console errors.
• CHROME_EXECUTABLE=/home/bl/.cache/ms-playwright/chromium-1243/chrome-linux64/chrome node scripts/browser-packed.mjs --indexed-sparse: PASS, cold/warm/three-worker/serial/concurrent/all-silent/tail proofs, all physical workers terminated, zero request failures and zero console errors.
• npm run check: PASS, including format, reproducible SHA-256/BLAKE3 Wasm, types/source policy, decoder policy, the complete test suite, and package policy.
• npm run check:package: PASS, 247 files and 474766 packed bytes.
• npm run publish:dry-run: PASS for unpublished action only, @misofm/engine-web-adapter@0.5.10, 247 files, package SHA1 39cb19c1f312af81c9905d4f50811107d093d3ee.
• git diff --check: PASS. Generated .adapter-71-evidence/ was removed; final status contains only this issue spec and scripts/browser-packed.mjs.

Verdict: PASS for the smallest packed-browser harness correction. Root retains ownership of checkpointing, remote delivery, review, and release sequencing.

Fresh Sol HIGH adversarial review

PASS on frozen commit 2e982947d752a66e04b427066de6ebe79cabe003. The reviewer confirmed exact two-path scope, the installed/current Engine host's only two relative companions, authoritative BUNDLED_ENGINE_FILES names, manifest-hashed directory construction, and byte-identical host/ABI/prepared-control output in both ordinary and indexed builds. Ordinary Chromium 153 passed full playback/control and observed the companion requests with correct JavaScript handling; indexed-sparse Chromium passed its complete matrix; both reported zero request and console failures. npm run check passed 380 tests, package policy remained 247 files/474766 bytes, dry-run package SHA1 remained 39cb19c1f312af81c9905d4f50811107d093d3ee, and the worktree was clean. No blocker remains for remote delivery.