Add background step syntax to workflow parser and language service

[lokesh755]

This change adds support for the new background step syntax in GitHub Actions workflows.

[Copilot]

Pull request overview

Adds support for “background steps” syntax in GitHub Actions workflows across the workflow parser and language service.

Changes:

• Extends the workflow schema/model to support background: true plus new step kinds: wait, wait-all, and cancel.
• Updates workflow template conversion logic and ID handling (including case-insensitive known-id tracking) to accommodate the new step types.
• Adds/updates reader fixtures and language service tests for validation and completions.

Show a summary per file

File	Description
workflow-parser/testdata/reader/errors-job-id-format.yml	Updates expected ID-format error text (fixes duplicated “and”).
workflow-parser/testdata/reader/error.yml	Updates expected “missing info” diagnostic to include new step kinds.
workflow-parser/testdata/reader/background-steps.yml	Adds fixture covering background + wait/wait-all/cancel parsing output.
workflow-parser/src/workflow-v1.0.json	Extends schema with new step types and background, plus definitions for wait/cancel fields.
workflow-parser/src/model/workflow-template.ts	Extends Step union/types to represent wait/wait-all/cancel and background.
workflow-parser/src/model/type-guards.ts	Adds isExecutableStep helper for steps that carry if/env/continue-on-error.
workflow-parser/src/model/converter/steps.ts	Converts new step fields/types; generates synthetic IDs for new step kinds; validates wait/cancel targets.
workflow-parser/src/model/converter/id-builder.ts	Makes known-id tracking case-insensitive; fixes error message text.
workflow-parser/src/model/converter/id-builder.test.ts	Adds test coverage for case-insensitive known-id tracking.
workflow-parser/src/model/convert.test.ts	Updates tests to only assert if on executable steps.
languageservice/src/validate.test.ts	Adds validation tests for accepting background-step keywords and rejecting wait-all: false.
languageservice/src/context/workflow-context.ts	Treats new step kinds as step mappings for context lookup.
languageservice/src/context-providers/env.ts	Restricts step env context to executable steps only.
languageservice/src/complete.test.ts	Updates step-key completion expectations to include new keywords.

Copilot's findings

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Comments suppressed due to low confidence (2)

workflow-parser/src/workflow-v1.0.json:2245

• step-wait-all-value is defined as null | boolean, but the converter/language service rejects wait-all: false. Because completions are schema-driven, this schema will also suggest false as a valid value. If false is intentionally invalid, consider tightening the schema/value providers so only the bare key (null) and true are offered/accepted (and keep conversion/diagnostics consistent with that).

    "step-wait-all-value": {
      "description": "Wait for all prior background steps to complete. Use as a bare key (`wait-all:`) or with a boolean value.",
      "one-of": [
        "null",
        "boolean"
      ]

workflow-parser/src/model/converter/steps.ts:249

• wait/cancel targets are described (in the schema) as referring to background steps, but this validation only checks that the referenced step ID exists. As a result, workflows can wait/cancel non-background steps without any diagnostic. Consider tracking which known step IDs were declared with background: true and validate that targets resolve to those background IDs (in addition to the existing existence/self/reserved checks).

  } else if (ownStepId && target.value.toLowerCase() === ownStepId.value.toLowerCase()) {
    context.error(target, `Step '${ownStepId.value}' cannot reference itself`);
  } else if (!idBuilder.hasKnownId(target.value)) {
    context.error(target, `Step references unknown step ID '${target.value}'`);
  }

• Files reviewed: 14/14 changed files
• Comments generated: 2

[lokesh755]

not all steps has env now.