Stop dependabot-validate's dev-smoke failing every Dependabot PR on theme repos

[mcarter-astronautdev]

Every Dependabot PR on foundrae-blackridge gets a red validate / validate check from dependabot-validate.yml@v1.17.0, so the check carries no signal there. Install, build and test all pass in its own build.log; the job then fails at dev-smoke ("crashed or no ready marker").

• The repo's npm run dev is run-p dev:shopify dev:vite, and shopify theme dev needs the Shopify CLI credentials the validator deliberately withholds. dev-smoke can never come up on a theme repo. Proof it is not the bump: #206 changes two ruby/setup-ruby pin lines and no code, and fails identically to the 11-package npm bump in #207.
• dev-smoke's output is not in the uploaded artifact, so the dependabot-report agent writes "cause not shown in the artifacts" and tells the reader to hold.
• The validator ran Node 22.23 against a repo whose engines/.nvmrc say 24 (EBADENGINE warning). Read .nvmrc or engines.node before setup-node.

Options: let a caller input skip dev-smoke (or point it at dev:vite only), and ship the dev-smoke log in the artifact either way.

from: foundrae-blackridge, PRs #206 and #207

[mcarter-astronautdev]

Different cause than filed. On foundrae #206 (run 36854681180) dev-smoke never ran — there is no .github/agent-validate.json on that repo, so no dev command is configured — and the step exits 1 right after "no test script", printing nothing. The registry-names pipeline in the reusable returns 1 under bash -e + pipefail whenever build.log has no npm error <pkg>@ line, i.e. on every clean run, and the step dies there before result.json is written (which is why the report agent sees no cause). Reproduced locally for the actions-bump, single-npm and grouped-npm body shapes. PRs with a real peer-dependency failure get past it (that line exists) and are reported properly, which is why it looked bump-specific. Fleet-wide since v1.15.0. Fix: one || true, PR #73; reaches the fleet with the v1.18.0 release. The Node-version point (.nvmrc / engines.node before setup-node) stands as a separate improvement.