Feature Request: Granular control over workflow validation diagnostics

首先檢視擴充功能目前如何產生 context-access、expression、schema 及其他驗證診斷，然後將這些路徑與提議的設定進行比較。完成條件應包括一個已達成共識的設定模型，讓使用者能夠啟用驗證，並控制或抑制診斷類別，同時不必停用 GitHub Actions 的語言功能。

Problem

The extension currently provides no user-configurable settings to control which validation diagnostics are shown in the Problems panel. Users cannot suppress specific categories of warnings/errors without disabling the extension entirely or changing file associations to plain YAML (losing all GitHub Actions language features).

Current Behavior

The extension surfaces diagnostics like:

• Context access might be invalid: <VAR_NAME> (severity: hint)
• Expression validation errors
• Schema validation warnings

These are generated for valid workflow patterns (e.g., outputs set via $GITHUB_OUTPUT and referenced in subsequent jobs) that the static analyzer cannot fully resolve.

Example

jobs:
  build:
    outputs:
      version: ${{ steps.version.outputs.DF_VERSION }}
    steps:
      - id: version
        run: echo "DF_VERSION=$(cat VERSION)" >> $GITHUB_OUTPUT
  
  deploy:
    needs: build
    steps:
      - run: echo "Deploying ${{ needs.build.outputs.DF_VERSION }}"
        # ⚠️ "Context access might be invalid: DF_VERSION"

The warning is a false positive—the workflow is correct, but the extension cannot trace the dynamic output.

Requested Feature

Add granular settings to control validation behavior, for example:

{
  "github-actions.validation.enabled": true,
  "github-actions.validation.severity": {
    "context-access": "ignore",      // or "hint" | "warning" | "error"
    "unknown-action": "warning",
    "deprecated-command": "hint",
    "schema": "error",
    "expression": "warning"
  }
}

Alternatively, a simpler approach:

{
  "github-actions.validation.suppressedRules": [
    "context-access",
    "deprecated-command"
  ]
}

Benefits

• Users can tailor validation to their workflow patterns
• Reduces noise from false positives without losing useful diagnostics
• Aligns with patterns in other linting extensions (ESLint, Pylint, etc.)

Workaround (Current)

The only workaround is to change file associations:

"files.associations": {
  ".github/workflows/*.yml": "yaml"
}

This disables all GitHub Actions features, which is undesirable.

Environment

• Extension version: 0.29.1
• VS Code version: 1.96.x
• OS: macOS