Make jobs.<job_id>.steps required in job-factory

[muzimuzhi]

Fixes github/vscode-github-actions#291.

This PR makes steps property required by jobs that don't call reusable workflows.

The only non-test change is

--- a/workflow-parser/src/workflow-v1.0.json
+++ b/workflow-parser/src/workflow-v1.0.json
@@ -1700,7 +1700,10 @@
           "concurrency": "job-concurrency",
           "outputs": "job-outputs",
           "defaults": "job-defaults",
-          "steps": "steps"
+          "steps": {
+            "type": "steps",
+            "required": true
+          }
         }
       }
     },

---

Without steps, such jobs won't even run. It's shown in muzimuzhi/hello-github-actions#33 that triggering workflow file

on:
  push:
  workflow_dispatch: # optional
jobs:
  no-steps:
    runs-on: ubuntu-latest

would fail with

Invalid workflow file: .github/workflows/test-github-actions.yml#L1
No steps defined in `steps` and no workflow called in `uses` for the following jobs: no-steps

[Copilot]

Pull request overview

This PR makes the steps property required for GitHub Actions jobs that use a runner (jobs with runs-on), aligning with GitHub Actions' actual validation behavior where jobs must have either steps defined or call a reusable workflow via uses.

Key changes:

• Updated the workflow schema to make steps required for job-factory type jobs
• Added a new test case to validate the error when steps is missing
• Updated existing test cases to include steps where previously omitted

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
workflow-parser/src/workflow-v1.0.json	Schema change making steps required for regular jobs (job-factory)
workflow-parser/testdata/reader/errors-job-runs-on-and-no-steps.yml	New test file validating the missing steps error
workflow-parser/testdata/reader/errors-job-runs-on-and-uses.yml	Updated test to include steps (problematic - see comment)
workflow-parser/src/model/convert.test.ts	Updated test workflows to include steps and added new test case
languageservice/src/validate.test.ts	Updated test workflows to include steps

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

Adding steps to a job that uses a reusable workflow (with uses) is incorrect. Jobs that call reusable workflows should not have steps - they delegate execution to the called workflow. This test case is validating that runs-on and uses cannot coexist on the same job. Adding steps here creates a confusing test case with multiple simultaneous validation errors (runs-on + uses + steps), when the test should focus solely on the runs-on + uses conflict.

Suggested change

	steps:
	- run: echo hello