Covers classify_gpu (decision-table over 28 GPU strings inc. boundary
values for AMD Radeon number ranges), _screen_tier resolution
classification, derive_font_prefs / derive_font_whitelist coherence and
determinism, and the public Forge / sample entry points (locked
identity, key set, type correctness, seed determinism).
One plan deviation: the original plan claimed `AMD FirePro W7100` →
`workstation`, but the workstation regex requires a `Radeon` prefix,
so FirePro alone falls through to the `mid_range` fallback. Test
asserts the actual behaviour.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
