Extend visibility tiers for DevOps and Functions

[TacoRocket]

What changed

• extend the visibility-tier validation seed to cover devops and functions
• keep the same shared-story approach while checking that weaker views preserve honest routing and explicit credential-scope issues
• add human-readable aliases for the high/medium/low tier names so test output is easier to map to admin-like, operator/dev-like, and user-like views

Why

• devops and functions are the next places where partial visibility can blur operator follow-up if we do not test the downgrade path directly
• the alias wording makes the tier tests easier to read without changing the underlying fixture structure

Validation

• python3 -m pytest tests/test_visibility_tiers.py tests/test_collectors.py tests/test_terminal_ux.py -k "''visibility_tiers or collect_devops or collect_functions or devops_table_mode or functions_partial''"
• python3 -m ruff check tests/test_visibility_tiers.py