Release: cleanup + explicit skill sources + Yarn PnP fix

[LadyBluenotes]

Tracking issue for a release shipping three related changes together on the pnp-and-cleanup branch. Two of them are breaking.

• Remove the abandoned intent-library bin #143 — Remove the abandoned intent-library bin (prerequisite for the allowlist work)
• Explicit skill sources (allowlist) #145 — Explicit skill sources (allowlist)
• Fix Yarn PnP discovery #144 — Fix Yarn PnP discovery (see discussion Add PnP support #119)

The cleanup (#143) unblocks the allowlist work (#145). The PnP fix (#144) is independent and can land on its own if needed.