Fix dispatch-workflow validation to run unconditionally

[Copilot]

Dispatch-workflow validation was gated behind the presence of agentic-workflows tool, allowing workflows with non-existent targets to compile successfully and fail at runtime.

Changes

• Moved validation: validateDispatchWorkflow() now runs for all workflows with dispatch-workflow configuration, independent of agentic-workflows tool presence
• Added test: TestDispatchWorkflowValidationWithoutAgenticWorkflowsTool verifies validation runs correctly

Impact

Previously silent at compile time:

safe-outputs:
  dispatch-workflow:
    workflows: [nonexistent]  # Compiled successfully

Now caught immediately:

error: dispatch-workflow validation failed: workflow 'nonexistent' not found in .github/workflows

Users with workflows compiled before this fix will need to recompile to get proper workflow_files mapping for runtime dispatch.

Original prompt

Fix issues when using safe outouts dispatch-workflow with workflows list:
Processing message 1/2: missing_tool
✓ Recorded missing tool: dispatch-workflow
Reason: The safeoutputs-dispatch-workflow tool is required to trigger workflows (add-name, add-emojis) but is not available in the current tool set. Cannot proceed with workflow dispatch as specified in instructions.

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