Upgrade to stable Effect 4.0.0

[fiws]

Changes

• Upgrade the Effect peer and development dependencies, plus @effect/vitest, from 4.0.0-rc.115 to stable 4.0.0.
• Refresh pnpm-lock.yaml and replace obsolete RC minimum-release-age exemptions with exact stable-version exemptions.
• Update the README installation instructions and changelog to require stable Effect v4.
• Keep the package release version and Playwright dependencies unchanged; no source API migration was required.

Verification

• pnpm install --frozen-lockfile
• pnpm type-check
• pnpm build
• pnpm test: 104 tests passed
• pnpm test:playwright: 12 passed, 2 skipped
• pnpm check-doc-examples: 31 TypeScript examples checked
• pnpm exec biome check package.json pnpm-workspace.yaml README.md CHANGELOG.md: passed for the supported package.json file
• Built-package Chromium smoke: DOM click behavior, typed timeout errors, and scoped browser cleanup after success, failure, and fiber interruption all passed.

---

Note

Low Risk
Dependency and documentation-only change; peer range tightens to stable Effect 4 with no runtime code changes in the diff.

Overview
Moves effect-playwright from Effect 4.0.0-rc.115 to stable effect@^4.0.0 and @effect/vitest@^4.0.0, with lockfile and pnpm-workspace.yaml minimum-release-age exclusions updated to match.

CHANGELOG now states that Effect 3 and Effect 4 prereleases are unsupported and consumers must use stable Effect 4. README drops the v4-branch callout and changes install to pnpm add effect@^4.0.0 effect-playwright instead of effect-playwright@next. No library source or Playwright version changes in this diff.

^{Reviewed by Cursor Bugbot for commit c9652fd. Bugbot is set up for automated code reviews on this repo. Configure here.}

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/effect-playwright@c9652fd

commit: c9652fd