Adds the tier subcommand to the hyperguild CLI. Reuses internal/tier.Detect verbatim, sources probe URLs from ANTHROPIC_PROBE_URL (default https://api.anthropic.com) and LITELLM_BASE_URL (no default — empty triggers airplane). Human-readable output by default; --json emits the same Info struct as the supervisor's tier MCP returns. Tests cover all three tier states via httptest fakes.