test: parallelize the integration pool and stop rebuilding shared artifacts (reland)

[ScriptedAlchemy]

Summary

• Relands test: parallelize the integration pool and stop rebuilding shared artifacts #25, which was merged into the already-landed test/prune-low-value-tests branch instead of main, stranding its changes.
• Cherry-picked onto main with two adjustments: the serial pool no longer lists the deleted inspector-shell.e2e.test.ts (removed with the vendored Inspector in feat(workbench): remove the vendored MCP Inspector in favor of an on-demand launcher #21), and a duplicated timeScale import in overview.e2e.test.ts (both branches added the same fix) is deduped.
• Splits integration tests into a parallel pool plus a one-worker serial pool (rstest.integration-serial.config.ts), moves pack-and-install tests to the test:packed scripts, and stops rebuilding shared artifacts per test file.

Test plan

• pnpm typecheck and pnpm rslint . clean
• Unit suite: 1,655 passed
• Full CI was green on test: parallelize the integration pool and stop rebuilding shared artifacts #25 before its mis-based merge
• CI on this PR against current main

[changeset-bot]

⚠️ No Changeset found

Latest commit: 72b1f56

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[chatgpt-codex-connector]

Codex Review Summary

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Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-08-29T04:05:03.545278Z	72b1f56	PR opened

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[pkg-pr-new]

npm i https://pkg.pr.new/ScriptedAlchemy/agent-bundle@28

npm i https://pkg.pr.new/ScriptedAlchemy/agent-bundle/@agent-bundle/rsc-runtime@28

commit: 72b1f56

[ScriptedAlchemy]

Superseded by #27, which contains these changes plus further pruning and is already reconciled with main.

[chatgpt-codex-connector]

💡 Codex Review

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Reviewed commit: 72b1f5608a

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