refactor(archive) tab split (phase 4 pt 3) : delete + maintenance helpers

[ebuzerdrmz44]

Description

Continues the ArchiveTab breakup started in #2519 (pt 1) and #2525 (pt 2, diff + rename). This peels the remaining destructive/maintenance actions out of the god-object into the same collaborator-class pattern under views/archive/:

• archive/archive_delete.py ArchiveDelete (delete_action / delete_result)
• archive/archive_maintenance.py ArchiveMaintenance (check, compact, prune actions + results, save_prune_setting, toggle_compact_button_visibility)

archive_tab.py shrinks by 130 lines and now just wires these helpers alongside the pt 2 ArchiveDiff / ArchiveRename.

No behavior change .

Notes

• Stacks on refactor(archive): peel diff and rename into views/archive/ helpers (Phase 4 pt 2) #2525. Until that merges, this PR's diff includes pt 2's commit; review only the top commit here. Kept as draft for that reason.
• The helpers call the tab's _set_status / _toggle_all_buttons. De-underscoring that tab/helper boundary is a deliberate later cleanup, kept consistent with pt 2 rather than widened here.
• Test call sites updated to the new module paths (tests/unit/test_archives.py, tests/integration/test_archives.py).

[m3nu]

Reviewed the pt-3 commit (93a4c93) in depth — it's a faithful, line-by-line move of delete/check/compact/prune into ArchiveDelete/ArchiveMaintenance, matching the extract/mount collaborator pattern. Selection goes through selected_archives() / ArchiveRole, so it's proxy-safe; helpers are strongly referenced on the tab, so the signal lifecycle is sound; all test call sites are updated with no stale patches.

Two nits before merge:

1. The description says toggle_compact_button_visibility moved into ArchiveMaintenance — it actually stays on the tab, which is correct (application.py calls archiveTab.toggle_compact_button_visibility()), but please fix the description.
2. The application.py string-literal cleanup hunk is unrelated to this PR. Harmless, but out of scope.

Once #2525 is squash-merged, rebase onto master (the diff collapses to the pt-3 commit) and un-draft — then this is good to go. Optional but cheap: a smoke test each for check_action/compact_action/prune_action, which currently have no direct coverage (pre-existing gap, not something this PR introduced).

The merge-base changed after approval.