fix: AI connection type propagation and get_node improvements (v2.28.1) (#461)

* fix: AI connection type propagation and get_node improvements (v2.28.1)

Bug fixes:
- Issue #458: addConnection now preserves AI connection types (ai_tool, ai_memory, ai_languageModel) instead of defaulting to 'main'
- Fixed false positive "AI Agent has no tools connected" validation warning

Enhancements:
- Added expectedFormat field to resourceLocator properties in get_node output
- Added versionNotice field to make typeVersion more prominent

Conceived by Romuald Członkowski - https://www.aiadvisors.pl/en

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* test: add missing test coverage for PR #461 improvements

- Added test for AI Agent validation positive case (tools properly connected)
- Added 3 tests for expectedFormat on resourceLocator properties

Conceived by Romuald Członkowski - https://www.aiadvisors.pl/en

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

---------

Co-authored-by: Claude <noreply@anthropic.com>

src/services/workflow-diff-engine.ts

@@ -757,7 +757,8 @@ export class WorkflowDiffEngine {
     const { sourceOutput, sourceIndex } = this.resolveSmartParameters(workflow, operation);
 
     // Use nullish coalescing to properly handle explicit 0 values
-    const targetInput = operation.targetInput ?? 'main';
+    // Default targetInput to sourceOutput to preserve connection type for AI connections (ai_tool, ai_memory, etc.)
+    const targetInput = operation.targetInput ?? sourceOutput;
     const targetIndex = operation.targetIndex ?? 0;
 
     // Initialize source node connections object