sam-styles pipeline modernization (SAM Angular upgrade pilot) — IAEMOD-57412

[fpigeonjr]

Pipeline & tooling modernization for @gsa-sam/sam-styles as the pilot for the SAM design-library Angular upgrade epic (IAEMOD-57412).

sam-styles ships no Angular (pure USWDS 3.3 SCSS), so it is the risk-free first tracer bullet: it proves the CI + publish pipeline that the four Angular libraries will inherit, with zero migration risk. Coordination/tracking lives on the internal research repo (mcaas-iae/iae-angular-upgrade issue #4).

Goal

Bring sam-styles up to the target pipeline: consistent Node, lint in CI, test + coverage, Dependabot, and an automated tag-gated npm publish (currently published manually).

Sub-tasks

• 1. Normalize Node version + remove stale CI config
• 2. Add stylelint to CI — quality rules only; formatting handled by Add Prettier and format the whole repo #739 (do Add Prettier and format the whole repo #739 first)
• 3. Add test + coverage step
• 4. Add Dependabot config
• 5. Add tag-gated publish workflow (dry-run; live publish handed to DevSecOps)

Notes

• No Angular work here — this repo is USWDS SCSS only.
• Live npm publish credential (@gsa-sam token) is owned by DevSecOps and wired in at sub-task 5.
• Epic: IAEMOD-57412.