feat(bun-test): add @effect/bun-test package

[emilienbidet]

Summary

Adds a new @effect/bun-test workspace package that mirrors the @effect/vitest
API surface (it.effect, it.live, it.layer, it.prop, flakyTest,
layer, …) but runs on Bun's built-in
bun:test runner instead of Vitest.

Companion PR to Effect-TS/effect#6236; addresses the same request as
Effect-TS/effect#5964.

Why

Quoting Effect-TS/effect#5964: Bun's test runner is significantly faster than
Vitest, and the Vitest dependency of @effect/vitest is a thin wrapper around
it() and describe() — the actual Effect test machinery (TestClock,
TestConsole, fast-check integration) is runner-agnostic. This PR ports that
thin wrapper to bun:test for the v4 line in effect-smol.

What's in the package

packages/bun-test/ mirrors packages/vitest/:

• src/index.ts — public API, types, re-exports of bun:test primitives
• src/internal/internal.ts — Effect runner + tester/layer/prop wrappers
  (uses Effect.fnUntraced, Layer.buildWithMemoMap, Layer.mergeAll(TestConsole.layer, TestClock.layer())
  to match the v4 vitest package shape)
• src/utils.ts — assertion helpers (copied from @effect/vitest utils.ts,
  vassert.instanceOf swapped for node:assert)
• test/index.test.ts — ported from packages/vitest/test/index.test.ts
• tsconfig.json, docgen.json, bunfig.toml, package.json, README.md,
  LICENSE

A changeset is included (.changeset/add-effect-bun-test.md).

Differences from @effect/vitest

Bun's test runner has a smaller surface than Vitest. The PR documents these
gaps in the package README; they were not papered over with runtime shims:

• addEqualityTesters is a no-op — bun:test's expect has no
  addEqualityTesters API.
• TestContext is synthesised inside the test wrapper rather than passed
  in by the runner, because bun:test doesn't pass a context object.
• re-export from \"bun:test\" doesn't work in Bun (1.2.x), so the public
  primitives are re-exported via const bindings rather than export *.

Test plan

• pnpm install at the workspace root resolves cleanly
• pnpm --filter=@effect/bun-test check passes
• bun test inside packages/bun-test is green
  • 24 pass, 4 skip, 0 fail
• Maintainers to decide whether CI should grow a Bun job for this package

Notes for review

• The layer > release test had its trailing afterAll(...) reordered so it
  runs after the layer's own afterAll (Bun runs afterAll hooks in
  registration order).
• The it.live.fails("interrupts on timeout", ...) test from the vitest suite
  was dropped because Bun has no fiber-interrupt-on-failure hook equivalent.
• No upstream files outside packages/bun-test/, .changeset/, and
  pnpm-lock.yaml were touched.

[changeset-bot]

🦋 Changeset detected

Latest commit: 60247dc

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 28 packages

Name	Type
@effect/bun-test	Major
effect	Major
@effect/opentelemetry	Major
@effect/platform-browser	Major
@effect/platform-bun	Major
@effect/platform-node-shared	Major
@effect/platform-node	Major
@effect/vitest	Major
@effect/ai-anthropic	Major
@effect/ai-openai-compat	Major
@effect/ai-openai	Major
@effect/ai-openrouter	Major
@effect/atom-react	Major
@effect/atom-solid	Major
@effect/atom-vue	Major
@effect/sql-clickhouse	Major
@effect/sql-d1	Major
@effect/sql-libsql	Major
@effect/sql-mssql	Major
@effect/sql-mysql2	Major
@effect/sql-pg	Major
@effect/sql-pglite	Major
@effect/sql-sqlite-bun	Major
@effect/sql-sqlite-do	Major
@effect/sql-sqlite-node	Major
@effect/sql-sqlite-react-native	Major
@effect/sql-sqlite-wasm	Major
@effect/openapi-generator	Major

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