[codex] Deprecate all-checks and tighten operator wording

[TacoRocket]

What changed

• marked all-checks and broad all-checks --section ... sweeps as deprecated across help, README, and runtime messaging
• tightened operator-facing wording so partial visibility is described in terms of what current credentials do and do not show
• updated CLI/help/UX tests to lock the new wording and deprecation surfaces in place

Why

The current product direction is to move grouped operator workflows toward chains while keeping flat commands available for narrower runs. This slice makes that direction explicit now and cleans up older wording that drifted into collector-oriented or tool-blaming language.

Impact

Operators now see clearer deprecation guidance around all-checks, and the visible text surfaces use more direct attacker-side language about current credential visibility.

Validation

• python3 -m pytest tests/test_help.py tests/test_cli_smoke.py tests/test_terminal_ux.py -q
• python3 -m ruff check src/azurefox/help.py tests/test_help.py tests/test_terminal_ux.py
• ACCR: no implementation-vs-plan drift found