fix(pin-state): replace removed Bluefin LTS HWE workflow paths

[castrojo]

Problem

scripts/fetch-pin-state.js requests build-regular-hwe.yml and build-dx-hwe.yml from projectbluefin/bluefin-lts, but both paths no longer exist.

Evidence

The GitHub contents API returns 404 for both workflow paths, and the script warns that their LTS pins cannot be fetched.

Expected

Read the active LTS workflow or authoritative image-version source so LTS pin information can populate.