ci: normalise dependency cache and node versions

[fredericoo]

WHY are these changes introduced?

• .github/workflows/test-calver.yml was still pinned to Node 18, which no longer matches the repo's supported runtime ("node": "^22 || ^24").
• pnpm cache setup in CI should consistently use the lockfile path for deterministic cache keys.

WHAT is this pull request doing?

• Updates .github/workflows/test-calver.yml to use node-version: '22'.
• Adds cache-dependency-path: 'pnpm-lock.yaml' to both .github/workflows/test-calver.yml and .github/workflows/test-upgrade-flow.yml.

HOW to test your changes?

1. Run the targeted CLI unit test:
   • pnpm --filter @shopify/cli-hydrogen test -- template-pack.test.ts
2. Confirm workflow changes in:
   • .github/workflows/test-calver.yml
   • .github/workflows/test-upgrade-flow.yml

Post-merge steps

None.

Checklist

• I've read the Contributing Guidelines
• I've considered possible cross-platform impacts (Mac, Linux, Windows)
• I've added a changeset if this PR contains user-facing or noteworthy changes
• I've added tests to cover my changes
• I've added or updated the documentation

[shopify]

Oxygen deployed a preview of your fb-ci-normalise-cache-and-node branch. Details:

Storefront	Status	Preview link	Deployment details	Last update (UTC)
Skeleton (skeleton.hydrogen.shop)	✅ Successful (Logs)	Preview deployment	Inspect deployment	February 24, 202612:03 PM

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