Addresses review feedback on #3486:
1. claude-thinking-legacy-alias now matches both claude-opus-4-6-thinking
and claude-opus-4-7-thinking, canonicalizing both to claude-opus-4-7.
The previous diff retargeted the regex to 4-7 only, which dropped
backward compatibility for users still pinned to the 4-6 thinking
suffix.
2. MODEL_TO_CATEGORY_MAP keeps the claude-opus-4-6 to unspecified-high
entry alongside the new 4-7 entry. The map is order-independent from
MODEL_VERSION_MAP, so preserving the 4-6 key avoids relying on a
specific migration ordering for legacy agent configs.
3. Fix stale 'Claude Opus 4.6' labels and BDD test comments that the
sed-based bump missed.
YeonGyu-Kim
5478bab457