# Add `@suaveplan/testing/runner` central runner subpath

**Package**: `@suaveplan/testing`
**Status**: PROPOSED
**Type**: feature

## Why

~95 packages currently import `describe`, `it`, `expect`, `vi`, and
`expectTypeOf` directly from `vitest`, which means the monorepo cannot
swap, wrap, or instrument the test runner without touching ~983 files.
`@suaveplan/testing-dom/runner` already provides this indirection for
DOM packages, but DOM/React-specific dependencies make it unsuitable as
the universal runner barrel. This change ports the same pattern into the
universal `@suaveplan/testing` package so every non-DOM package can
import the runner from one stable place.

## What changes

- ADDED: `@suaveplan/testing/runner` subpath export (vitest by default,
  `bun:test` under the `bun` package.json condition)
- ADDED: `src/runner/index.ts`, `src/runner/vitest.ts`,
  `src/runner/bun-test.ts`, `src/runner/mocks.ts` exporting
  `describe`, `it`, `test`, `expect`, `expectTypeOf`, `vi`,
  `beforeAll`, `beforeEach`, `afterAll`, `afterEach`,
  `fn<TArgs, TReturn>`, `spy`, `stub`, `mock`, `fakeClock`,
  `restoreMocks`, `restoreTimers`, plus types `RunnerMock`, `SpyHandle`
- ADDED: `expectTypeOf` shim for the bun-test path (Proxy-backed no-op
  chain — type assertions are erased at compile time)
- ADDED: `@types/bun` devDependency, `tsconfig.lib.json` `types` extended
  with `bun`, and matching vite multi-entry build wiring
- ADDED: `runner/mocks.test.ts` and `runner/runner.spec-conformance.test.ts`

## Out of scope

- Migrating ~983 vitest imports to the new subpath — handled in a
  follow-up codemod commit (genesis branch, same PR)
- DRY-linking `@suaveplan/testing-dom/runner` to this subpath — rule 8
  forbids `testing-dom` from depending on `@suaveplan/testing`, so the
  two surfaces stay duplicated by design

## Verification approach

- `src/runner/mocks.test.ts` — unit coverage for `fn`/`spy`/`stub`/
  `fakeClock`/`restoreMocks`/`restoreTimers`
- `src/runner/runner.spec-conformance.test.ts` — type-level pins via
  `expectTypeOf` for `RunnerMock<TArgs, TReturn>` and `SpyHandle`
- 5-gate triple (`bun run check`, `turbo lint typecheck test`,
  `turbo test:coverage` 100/100/100/100, openspec-conformance,
  `turbo build`) green for `@suaveplan/testing`

## Migration impact

Additive only. No existing exports change. Consumers continue to import
the package barrel for utilities; the new `./runner` subpath is the sole
addition.