feat(app): add archived sessions browser dialog

[ohsalmeron]

Closes #36929

Adds a /archived command that opens a dialog listing all archived sessions sorted by archive date. Clicking a session navigates to it.

[github-actions]

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[github-actions]

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

Potential Duplicate Found:

• PR feat(app): view archived sessions & unarchive #15250: feat(app): view archived sessions & unarchive
  • This PR appears to address the same feature: viewing archived sessions. The existing PR may already implement the functionality to browse and interact with archived sessions. Check if it's still open or if it was closed without being merged, which would explain why a new PR for this feature is needed.

[github-actions]

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