piecrust: remove zero-cost host query blanket impl

[d-sonuga]

No description provided.

[Copilot]

Pull request overview

Removes the “zero-cost” blanket HostQuery implementation for Fn(&mut [u8], u32) -> u32, making host-query pricing explicit and preventing accidental zero-gas host queries in the Piecrust VM API.

Changes:

• Removed the blanket HostQuery impl for host query closures from piecrust/src/vm.rs.
• Updated host-query tests to wrap function-based queries in an explicit ZeroCostHostQuery adapter.
• Added a CHANGELOG.md entry documenting the removal.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
piecrust/tests/host.rs	Adds an explicit ZeroCostHostQuery wrapper and updates test registrations accordingly.
piecrust/src/vm.rs	Removes the blanket HostQuery implementation for Fn(&mut [u8], u32) -> u32.
piecrust/CHANGELOG.md	Documents the removal under Unreleased → Removed.

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[moCello]

APPROVE — Clean, well-scoped removal of a zero-gas footgun. The test wrapper preserves behavior, all in-tree registrations are updated, and downstream (rusk/vm) already uses explicit HostQuery impls, so nothing breaks. One optional nit: capitalize "Remove" in the commit subject to match the repo convention.

[d-sonuga]

capitalize "Remove" in the commit subject to match the repo convention.

There is no repo convention that says that. Over 90% of commits with a "piecrust: " prefix does not have capitalization.

[HDauven]

LGTM