feat: 6.4.2 release (#796)

Co-authored-by: webiny-bot <webiny-bot@webiny.com>

Author: github-actions[bot]

docs/release-notes/6.4.2/changelog.ai.txt

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+AI Context: 6.4.2 Changelog (changelog.mdx)
+
+This file tracks manual edits made after the generation script ran.
+The script reads the "Skipped PRs" section to avoid re-adding removed entries.
+
+## Skipped PRs
+
+## Manual Rewrites

docs/release-notes/6.4.2/changelog.mdx

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+---
+id: n2xj47qb
+title: Webiny 6.4.2 Changelog
+description: See what's new in Webiny version 6.4.2
+---
+
+import { GithubRelease } from "@/components/GithubRelease";
+import { Alert } from "@/components/Alert";
+
+<GithubRelease version={"6.4.2"} />
+
+## Headless CMS
+
+### Fixed Publishing a Previously Unpublished Revision ([#5268](https://github.com/webiny/webiny-js/pull/5268))
+
+When a published CMS entry revision was unpublished and then you attempted to publish it again, the operation would fail because the record was incorrectly marked as locked. This has been fixed — you can now re-publish previously unpublished revisions without issues.
+
+## Admin
+
+### Fixed Date Formatting Compatibility ([#5270](https://github.com/webiny/webiny-js/pull/5270))
+
+Relative date formatting (e.g., "2 hours ago") in the Admin UI was using the Temporal API, which isn't fully supported across all browsers. This has been replaced with a more compatible implementation to ensure consistent behavior.
+
+## Website Builder
+
+### Visual Improvements in Page Editor ([#5272](https://github.com/webiny/webiny-js/pull/5272))
+
+Several UI inconsistencies in the Website Builder page editor have been addressed. Input fields now render with consistent sizing and styling. Additionally, the orange selection border that previously shifted position when scrolling is now stable and remains fixed in place.

docs/release-notes/6.4.2/upgrade-guide.mdx

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+---
+id: h20auv85
+title: Upgrade from 6.4.x to 6.4.2
+description: Learn how to upgrade Webiny from 6.4.x to 6.4.2.
+---
+
+import { Alert } from "@/components/Alert";
+import { AdditionalNotes } from "@/components/upgrade/AdditionalNotes";
+
+<Alert type="success" title="What you'll learn">
+
+- how to upgrade Webiny from 6.4.x to 6.4.2
+
+</Alert>
+
+<Alert type="info">
+
+Make sure to check out the [6.4.2 changelog](./changelog) to get familiar with the changes introduced in this release.
+
+</Alert>
+
+## Step-by-Step Guide
+
+### 1. Upgrade Webiny Packages
+
+Upgrade all Webiny packages by running the following command:
+
+```bash
+yarn webiny upgrade 6.4.2 --debug
+```
+
+Note that the command above will run upgrades for all available versions of Webiny up to 6.4.2. If there are upgrades for 6.4.1, 6.4.5, they will be ran.
+
+You can omit the version to upgrade to the latest available:
+
+```bash
+yarn webiny upgrade --debug
+```
+
+Once the upgrade has finished, running the `yarn webiny --version` command in your terminal should return **6.4.2**.
+
+<Alert type="info">
+
+If the above command fails or is not available in your setup, you can run the upgrade script directly via `npx`:
+
+```bash
+npx https://github.com/webiny/webiny-upgrades-v6 6.4.2 --debug
+```
+
+</Alert>
+
+### 2. Deploy Your Project
+
+Proceed by redeploying your Webiny project:
+
+```bash
+# Execute in your project root.
+yarn webiny deploy --env {environment}
+```
+
+<AdditionalNotes />