v1.9 — setup-bun keeps its cache under skip-install; Playwright gets a directory

• setup-go defaults to golangci-lint v2.13.2, built with go1.27.0. v2.12.2 was
  built with go1.26.2 and cannot lint any module declaring go 1.27, which is 30
  of the fleet's Go modules.
• setup-bun's install-store cache is gated on the lockfile existing rather than
  on skip-install, restoring caching to callers that install later themselves.
• Both Bun actions take playwright-directory, so a workspace can pin the browser
  version against the app's package.json instead of the install root's.
• setup-nextjs-bun gains the extra-cache inputs setup-bun already had.
• setup-go drops lint-install-only, which reported a green gate for a lint that
  never ran.
• Both Bun actions resolve the Playwright version with bun instead of node.