feat: archive users instead of deleting, and save the user page with one button

[thomasbeaudry]

Summary

Depends on DouglasNeuroInformatics/libui#121. The account Status field's ? help only opens its description on hover once that PR is merged, released, and the @douglasneuroinformatics/libui catalog version here is bumped (mind the 7-day minimumReleaseAge). Until then it still works, but on click only. Nothing else in this PR depends on it.

Archive replaces delete

• Delete User is gone. Admins Archive a user (with confirmation) or Unarchive them, from the user page or the users table's row actions. An admin cannot archive themselves.
• Archiving sets a new archivedAt date instead of reusing disabled, which keeps its own meaning (an account never meant to log in, exempt from needing a group). Both actions are written to the audit log.
• The users table gains sortable headers, an Enabled / Disabled column, and a Status column showing Active or Archived on .
• Login tells an archived or disabled user why they cannot sign in, but only once their password is verified, so a wrong guess cannot reveal whether a username exists or what state it is in.

One Save button on the user page

• The permissions table no longer saves on every change. A single Save Changes button below it saves the account details and permissions together; the account form's own button is removed.
• The plus icon only adds a permission row. A filled-in row is saved by Save without pressing plus; a half-filled row blocks the save and is highlighted, rather than being silently dropped.
• The account Status field now reads Status ? with Enabled / Disabled on one line, Enabled first and preselected, and clearer help text.

Also merges main and adds Spanish to every string on the rewritten user page.

Test plan

• pnpm lint passes
• pnpm test: 1566 unit tests pass, including new ones for archive/unarchive, login status ordering, the single-save mutation, incomplete permission rows and the users table columns
• pnpm test:e2e: the admin-management and authorization specs pass (75 tests) after the single-save change
• pnpm test:e2e full suite on the final branch. Not run locally since the incomplete-row, login-ordering and Status-field changes and the merge with main; relying on CI
• Manually check the user page: archive/unarchive, save with a half-filled permission row, Status field layout

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