feat: manage Node 24 across shared workflows

[artiphishle]

Summary

• add a canonical Node 24 LTS tooling policy alongside the existing Bun 1.3.14 policy
• make managed CI explicitly install Node 24 instead of inheriting the runner's ambient Node version
• render both CI and release workflow Node versions from the shared policy
• add coverage proving managed workflows contain the canonical Bun and Node versions

Why

Ankhorage now treats Node 24 LTS as the baseline wherever Node-based tooling executes. The managed CI workflow already invokes node for script detection and Expo/tooling consumers can execute Node-based CLIs, so CI should not depend on whatever Node version happens to be preinstalled on ubuntu-latest.

The release workflow already selected Node 24 explicitly; this change makes that selection centrally owned instead of hardcoded independently.

Policy

• Bun remains the package manager / primary repository command runtime where configured.
• Bun remains centrally managed at 1.3.14.
• Node 24 is the deterministic baseline for Node-based tooling/CI.
• consuming repositories should receive these workflow changes through ankh devtools sync, not by manually editing managed workflow files.

Validation

CI should validate build, tests, typecheck, lint, format, Knip, docs, and Changesets as usual.