Setup CodeActions and add quickfix for missing inputs

[rentziass]

This PR adds CodeAction capabilities to the language server and sets up the inner loop for them, using workflow files where to define expected diagnostics and golden files to specify expected results. This also adds a CodeActionKind.QuickFix for when an action is used but it's missing required inputs:

[Copilot]

Pull request overview

This PR introduces CodeAction capabilities to the GitHub Actions language server, specifically implementing a quickfix feature for automatically adding missing required action inputs. The implementation includes:

• A new code action infrastructure with a provider-based architecture
• A quickfix provider that generates edits to add missing required inputs
• Test infrastructure using golden files to validate code action behavior
• Enhanced diagnostic data to support code actions

Reviewed changes

Copilot reviewed 16 out of 16 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
languageservice/src/code-actions/index.ts	Main entry point for code actions, implementing provider aggregation and filtering logic
languageservice/src/code-actions/types.ts	Type definitions for code action context and provider interface
languageservice/src/code-actions/quickfix/index.ts	Exports quickfix providers array
languageservice/src/code-actions/quickfix/add-missing-inputs.ts	Implementation of the quickfix provider for adding missing required inputs
languageservice/src/code-actions/tests/runner.ts	Test infrastructure for running golden file tests
languageservice/src/code-actions/tests/runner.test.ts	Test suite using the golden file runner
languageservice/src/code-actions/tests/testdata/quickfix/*.yml	Test input files with markers for expected diagnostics and fixes
languageservice/src/code-actions/tests/testdata/quickfix/*.golden.yml	Expected output files after applying code actions
languageservice/src/validate-action.ts	Enhanced validation to include diagnostic data needed for code actions
languageservice/src/validate.actions.test.ts	Updated tests to verify new diagnostic data fields
languageservice/src/index.ts	Exports the new getCodeActions function
languageserver/src/connection.ts	Registers code action handler and declares CodeActionKind.QuickFix capability

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[ericsciple]

Instead of assuming 2, have you considered matching the customer's indent? You could detect this based on the indent amount of the first job. For example:

function detectIndentSize(rootToken: MappingToken): number {
  const jobsValue = rootToken.find("jobs");
  if (jobsValue && isMapping(jobsValue) && jobsValue.count > 0) {
    const firstJob = jobsValue.get(0);
    if (firstJob?.key.range && jobsValue.range) {
      return firstJob.key.range.start.column - jobsValue.range.start.column;
    }
  }
  return 2; // fallback
}

[rentziass]

Done, thank you ❤️ I wonder if indent size is something we wanna carry around with WorkflowTemplate itself, I suspect it'll keep coming in use 🤔