Add presence set-preferred and clear-preferred

[aberoham]

presence set-preferred and presence clear-preferred manage the user-preferred presence, which Microsoft Graph ranks above every presence session while one exists.

• The Teams client's "Appear offline" is a preferred presence of Offline/OffWork. With it set, presence set returns success and the account stays offline, and no command could clear it.
• set-preferred --availability A [--expiration D] calls setUserPreferredPresence. Graph accepts Available, Busy, DoNotDisturb, BeRightBack, Away and Offline, each with one fixed activity, so the activity is derived from the availability and reported back.
• --expiration is checked as a positive ISO 8601 duration and not bounded. Graph documents defaults of one day for Busy and DoNotDisturb and seven days otherwise, rather than a range, so the PT5M to PT4H check on set does not apply here.
• clear-preferred calls clearUserPreferredPresence with the documented {} body. A second clear with nothing to clear returns 200, so there is no 404 to translate.
• Both commands reject an app-only token locally, as the other presence writes do.
• README, command reference, man page, CHANGELOG and the command lists in CLAUDE.md and AGENTS.md are updated.

Sample output:

{"status": "preferred_presence_set", "availability": "Away", "activity": "Away", "expiration_duration": "PT1H"}

{"status": "preferred_presence_cleared"}

Verified against a live tenant on 2026-09-03: an account carrying Offline/OffWork with an open Available session read Available/Available after clear-preferred; set-preferred --availability Away read Away/Away through both presence get and presence get-batch; a second clear-preferred returned 200.

[aberoham]

Adversarial review completed against base 979791f through the updated head 90466fe.

Findings fixed:

• In 06a655f, the duration parser was fixed to reject malformed P1DT. A trailing T had been treated as an empty but valid time section, allowing an invalid value to reach setUserPreferredPresence despite the command promising local ISO 8601 validation. Unit and black-box regression coverage were added.
• In 06a655f, exact v1.0 /me presence endpoint assertions were added. The previous Wiremock tests injected URLs and therefore did not cover the production endpoint builders.
• In 06a655f, command-path coverage for app-only rejection and help-JSON coverage for both new subcommands and the required availability flag were added; the auth guide and PRD command documentation were completed.
• In 06a655f, the docs were clarified to state that the CLI accepts positive whole-unit day/hour/minute/second durations rather than every possible ISO 8601 duration form.
• In 90466fe, the locked optional rand dependency was updated from 0.9.2 to patched version 0.9.3, clearing informational unsoundness advisory RUSTSEC-2026-0097. The affected dependency was only present through the unused optional HTTP/3/Quinn path in Reqwest, and the CLI has no direct Rand use or custom log::Log implementation, so I found no reachable exploitation path; the update removes the advisory regardless.

Validation completed:

• cargo audit: clean; 321 dependencies scanned
• cargo fmt -- --check
• cargo check --all-targets
• cargo clippy --all-targets -- -D warnings
• cargo test --all-targets: 250 unit tests and 69 black-box tests passed
• cargo build --release
• Direct probes confirmed malformed P1DT exits 2 while valid P1DT1S proceeds to authentication

I also checked the current Microsoft Graph v1.0 documentation for setUserPreferredPresence and clearUserPreferredPresence against the URL, request-body, pair, default-expiration, response, and delegated-permission behavior used here. I did not repeat the live-tenant writes already documented in the PR.

The fork-origin GitHub Actions run currently shows action_required with no jobs, so hosted Ubuntu/macOS/Windows CI remains pending approval.

No further code, dependency, or documentation findings remain. Merge-ready once hosted CI is approved and passes.