[Dmytro Kirpa (dmytrokirpa)]

Previous Behavior

DatePicker Preview is implemented but private and not included in the public v9 docsite or playground.

New Behavior

• Use the workspace initial-release generator to remove private from @fluentui/react-datepicker-preview and register it with the public docsite.
• Add its public playground module and regenerate the lockfile with Yarn.
• Add a public DatePicker component bundle fixture and the initial minor Beachball change file.
• Keep the preview package name and production-readiness disclaimer. Package versioning remains owned by the release pipeline; this PR does not publish to npm or promote the package to stable.

Blocked draft: inherits the implementation layer's prerequisite on #36917. Rebase after Calendar merges. Publication/API approval and the documented human verification gates remain outstanding.

Validation

Validation used the exact Calendar prerequisite patch temporarily, removed before committing:

• NX_DAEMON=false yarn nx g @fluentui/workspace-plugin:prepare-initial-release --project react-datepicker-preview --phase preview --dry-run --no-interactive — passed; reviewed the generated library/docsite manifest changes.
• NX_DAEMON=false yarn nx g @fluentui/workspace-plugin:prepare-initial-release --project react-datepicker-preview --phase preview --no-interactive — passed; generated the minor release change file.
• yarn install --mode=skip-build — passed with existing workspace peer warnings; committed only the related lockfile changes.
• NX_DAEMON=false yarn nx run react-datepicker-preview:bundle-size --excludeTaskDependencies --skipNxCache — passed: 243.433 kB minified / 71.283 kB gzip.
• NX_DAEMON=false yarn nx run-many -t type-check lint -p react-datepicker-preview react-datepicker-preview-stories --excludeTaskDependencies --skipNxCache — passed.
• NX_DAEMON=false yarn nx run public-docsite-v9:type-check --excludeTaskDependencies --skipNxCache — passed after rebuilding stale playground addon declarations with NX_DAEMON=false yarn nx run react-storybook-addon-playground:build --excludeTaskDependencies --skipNxCache; no addon source/report changes.
• Packed the package through the DatePicker Nx target with yarn pack; inspected that ESM/CommonJS entry points and both declaration formats exist, the private flag is absent, and workspace dependency ranges are rewritten.
• Node smoke checks against the generated ESM and CommonJS exports — passed for DatePicker, its public hooks, and renderer.
• git diff --cached --check — passed.
• Full docsite build, CI screenshot approval, and manual screen-reader/browser/zoom acceptance — not run in this publication-only layer. Runtime/browser test evidence is recorded in the implementation PR.

Related Issue(s)

• Part of the DatePicker stack starting at feat(react-datepicker-preview): scaffold package and DatePicker component #36914.
• Blocked by fix(react-calendar-preview): preserve popup focus and compat geometry #36917; no separate linked issue.