Discover OMP Webster models dynamically

[theFong]

Summary

• query the authenticated Webster /models catalog during OMP setup
• preserve an accessible installed default (including OMP reasoning suffixes), otherwise prefer glm-5.2 or fall back deterministically
• keep OMP LiteLLM discovery enabled so every model accessible to the key appears in the picker
• validate empty, malformed, unreachable, and inaccessible-model cases

Validation

• bash -n omp-setup.sh
• bash -n test.sh
• ./test.sh
• git diff --check
• actionlint .github/workflows/bootstrap.yml
• live installer run and idempotent --check --no-smoke
• omp models refresh && omp models webster --json returned all 4 models accessible to the configured key
• live default-model smoke test returned OMP_OK