feat: add session archive/unarchive GUI support (v2)

[B67687]

Summary

• Adds archived sessions tab to Settings (Data section)
• Users can view and restore archived sessions from Settings → Archived Sessions
• Works with existing backend archive/unarchive support in dev

Changes

• Added SettingsArchive component (settings-archive.tsx)
• Added Data section with Archive tab to settings dialog
• Added i18n keys for archive UI strings

Test Plan

• Open Settings → verify Archive tab appears in Data section
• Archive a session via TUI /archive command
• Open Settings → Archived Sessions tab
• Verify archived sessions appear
• Click restore and verify session reappears in sidebar

See also: TUI PR #22372 (merge these together or separately)

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[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Potential Duplicate PRs Found:

1. PR feat: session archive/unarchive GUI support (rebase of #15250) #22400 - "feat: session archive/unarchive GUI support (rebase of feat(app): view archived sessions & unarchive #15250)"

   • feat: session archive/unarchive GUI support (rebase of #15250) #22400
   • This is explicitly a rebase of the older PR and appears to be directly related to the same feature.

2. PR feat(app): view archived sessions & unarchive #15250 - "feat(app): view archived sessions & unarchive"

   • feat(app): view archived sessions & unarchive #15250
   • This is the original implementation of session archive/unarchive GUI support that PR feat: session archive/unarchive GUI support (rebase of #15250) #22400 was rebased from.

Why they're related: These PRs all address the same feature—adding GUI support for archiving and unarchiving sessions. PR #22400 is explicitly a rebase of PR #15250, and the current PR #22406 (v2) appears to be another iteration on the same functionality. You may want to consolidate or coordinate with these existing PRs.

[github-actions]

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