hal0 v0.8.2b2

Two fixes on the 0.8.2 beta line — profile MTP tuning now actually takes
effect, and stacks can pull their referenced models. Safe upgrade from
v0.8.2b1.

Fixed

• Explicit profile spec flags win over the MTP bundle. resolve_profile_flags
  appended MTP_FLAG_BUNDLE after a profile's own flags, so the bundle's
  spec-draft defaults (--spec-draft-type-k q8_0, --spec-draft-p-min 0.0)
  silently clobbered any --spec-draft-* a profile pinned — there was no way to
  tune the MTP draft through a profile. The bundle is now merged as defaults that
  the profile's explicit flags override (gap-filled only). (#963)
• Absent stack models can be pulled. Custom GGUF builds referenced by the
  seed stacks (saber, pi-agent, qwopus coders, halostrix, gemma, …) were
  auto-scanned with empty hf_repo/hf_filename, so on stack import/apply they
  classified "unresolvable" with no download URL. Registered their public HF
  coordinates (jcbtc/ + Jackrong/ + unsloth/ repos) in the curated catalogue;
  embed_references falls back to curated on export; and a new
  backfill_coordless() repairs existing coord-less registry rows on rescan. (#964)

Changed

• CI: cancel superseded PR runs (never main); PRs test Python 3.12 only while
  main runs 3.12/3.13/3.14 (3.14 non-blocking); least-privilege workflow
  permissions; Node 20 → 22. (#898)