[experiment] Benchmark pnpm vs Bun on CircleCI

[Finesssee]

Experiment only

Do not merge. This draft PR exists only to activate the repository's CircleCI GitHub App webhook path for a package-manager benchmark.

Three equal Windows win/default medium lanes run the same Node/Vitest/TypeScript/Vite workload after dependency installation:

• current pnpm 11.24.0
• proposed pnpm 11.25.0
• Bun 1.4.2

The Bun lane uses an experiment-only bun.lock plus minimumReleaseAge = 86400, isolated linking, and disabled dependency lifecycle scripts. Node remains the runtime for tests/build tools so this measures package management rather than Bun-runtime compatibility.

Plan: one cold-cache run followed by two unchanged warm-cache runs. No product/release behavior should be merged from this PR.

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[Finesssee]

Bun-only runtime benchmark result

Completed three real CircleCI Windows win/default medium runs with Node, npm, Corepack, and pnpm explicitly removed from PATH before the JS workload.

Run	Bun install	Vitest under Bun	Production build under Bun	Tauri CLI	Fully Bun-only
1	4.041s	FAIL, 27/48 files	PASS, 12.177s	PASS	No
2	2.048s	FAIL, 27/48 files	PASS, 13.104s	PASS	No
3	2.034s	FAIL, 27/48 files	PASS, 10.095s	PASS	No

Every run independently asserted node, npm, corepack, and pnpm were unavailable.

Conclusion: Bun 1.4.2 can replace pnpm for install and can drive the production frontend build + Tauri CLI without Node, but Win-CodexBar cannot remove Node yet because the current Vitest/jsdom test contract is not compatible with Bun's runtime.

Additional disposable migration probe using Bun-native bun test + Happy DOM + a small vi compatibility shim improved discovery to 265 tests, but still left 79 failures + 10 errors. Concrete blockers include 40 vi.hoisted uses, 5 partial vi.mock(... importOriginal ...) factories, missing/incompatible vi.setSystemTime and other mock/timer/global helpers, plus accessor-spy differences.

This remains an experiment-only draft and should not be merged as-is.

[Finesssee]

Thermo-nuclear review: KEEP AS EXPERIMENT / DO NOT MERGE

That matches the PR's own stated intent. The benchmark harness is isolated from product runtime, but the current branch does not reproduce the full three-lane experiment described in the body:

• current head: experiment/bun-pnpm-circleci-20260906
• bun-only-runtime is filtered to that branch
• the three pm-benchmark jobs are filtered to experiment/bun-pnpm-circleci-completed

So a fresh run of this PR head exercises the Bun-only lane, not all three equal pnpm-11.24 / pnpm-11.25 / Bun lanes. If this PR remains as evidence, document the completed-branch runs/results explicitly. Do not merge the experiment-only bun.lock, bunfig.toml, benchmark scripts, or CircleCI routing into the product branch from this PR.

1k/CUA: no production code threshold or UI proof requirement applies.