model-overlays/ had no entry for the current Claude generation, so every
session on a Claude 5 family or Opus 4.8 model fell through to the generic
claude.md nudges. Adds the three overlays with resolver mappings and
per-overlay tests; generated output for the default host is unchanged
(overlays activate by detected model).
Closes#2509.
Contributed by @chrisquorum (PRs #2246, #2243, #2247).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Garry Tan