docs(ocis): add 8.2 updates — clean-corrupt-public-shares CLI

[DeepDiver1975]

Port of owncloud/docs-ocis#1285 ("docs: updates required for 8.2", by @mmattel) into the monorepo.

That PR never merged upstream, so ocis 8.2 shipped without this content and no version folder here carries it.

Important

Base branch is docs/ocis-8.1-updates (#62), not main — a deliberate chain, because both ports edit commands.adoc in content/ocis/8.2 and 8.3. Basing on #62 keeps this diff to its own 7 files instead of showing a conflict. Upstream's own PR body says the same thing: "it is important to merge this PR AFTER the 8.1 work has finished".

Merge order: #61 (merged) → #62 → this. Retarget to main once #62 lands.

Where the changes land

Substantive content → content/ocis/8.2 and 8.3:

Change	File
new Clean Corrupt Public Shares page (+33)	admin/pages/maintenance/commands/clean-corrupt-public-shares.adoc
its index entry (inserted before Cleanup Orphaned Grants)	admin/pages/maintenance/commands/commands.adoc
the command added to the COMMANDS: help listing, column re-aligned	admin/partials/maintenance/ocis-shares-cli.adoc

Version bookkeeping → content/ocis/8.2 only:

Change	File
:description: → 8.1.0 → 8.2.0 delta, and the delta bullet list	admin/pages/maintenance/commands/changed-cli.adoc

Corrected while porting

Upstream wrote the delta as "between … 8.0.0 and 8.1.0" — a leftover from when the branch's base was still the 8.1 dev line, which contradicts the PR's own "updates required for 8.2" title. Corrected to 8.1.0 → 8.2.0, the delta that content/ocis/8.2 actually describes.

This is also why the two ports no longer collide: #62 sets the 8.1 folder's delta page, this one sets the 8.2 folder's, and neither touches the other's.

Verification

• npm run antora → exit 0. Error/warning count is 41, identical to docs(ocis): add 8.1 updates — vault mode, blobstore CLI, 8.0→8.1 upgrade guide #62's — i.e. this PR adds none. Zero mentions of clean-corrupt, corrupt-public or shares-cli in the log. The 28 target of xref not found: next@ocis:… errors are pre-existing in content/main/modules/ROOT/pages/ocis_release_notes.adoc, untouched here.
• npm test → 17/17 pass.
• clean-corrupt-public-shares.html renders in both public/ocis/8.2/ and public/ocis/8.3/.
• Per-version delta pages read as designed: 8.1 → 8.0.0 and 8.1.0, 8.2 → 8.1.0 and 8.2.0, 8.3 → unchanged.

Refs: owncloud/docs-ocis#1285.

Addresses the upstream issue this content was written for, now migrated into this repo: #85 (owncloud/docs-ocis#1275).
Refs #44