feat: add release archiving and status filters

[stevenle]

Motivation

• Provide the ability to archive a Release so releases can be hidden from active lists and excluded from publish/schedule flows.
• Surface archived status in the UI and let users filter the Releases list by status using a segmented control.

Description

• Add archivedAt and archivedBy to the Release interface and a new archiveRelease() helper in packages/root-cms/ui/utils/release.ts to record archive metadata.
• Prevent publishing or scheduling of archived releases by returning an error in publishRelease() and scheduleRelease() when archivedAt is set.
• Update ReleaseStatusBadge to render an Archived badge (with tooltip) when a release is archived.
• Add an Archive action (with confirmation modal) to the Release detail page status panel and hide publish/schedule controls for archived releases in ReleasePage.
• Replace the Releases list with a Mantine SegmentedControl in ReleasesPage to toggle filters (Active / Unpublished / Published / Archived) and implement filtering where Active shows non-archived releases (published + unpublished).

Testing

• Attempted to build the UI with pnpm -C packages/root-cms build:ui but the environment could not download pnpm from the npm registry due to network/proxy restrictions and the build did not run.
• Attempted a Playwright screenshot of /cms/releases but no local app server was available at http://localhost:3000, so the UI validation could not be completed.
• No automated unit/visual tests were added or executed as per instructions.

Screenshots

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Codex Task