perf: optimize workflow tool responses for token efficiency (v2.29.0) (#479)

* perf: optimize workflow tool responses for token efficiency (v2.29.0)

Reduce response sizes by 75-90% for 4 workflow management tools:

- n8n_update_partial_workflow: Returns {id, name, active, operationsApplied}
- n8n_create_workflow: Returns {id, name, active, nodeCount}
- n8n_update_full_workflow: Returns {id, name, active, nodeCount}
- n8n_delete_workflow: Returns {id, name, deleted: true}

AI agents can use n8n_get_workflow with mode 'structure' if they need
to verify the current workflow state after operations.

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>

* fix: update tests and add nodeCount to partial update response

- Fix handleCreateWorkflow test to expect minimal response
- Fix handleDeleteWorkflow test to expect minimal response
- Add nodeCount to n8n_update_partial_workflow response for consistency
- Update documentation and CHANGELOG

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>

* fix: update handlers-workflow-diff tests for minimal response

Update 3 more tests that expected full workflow in response:
- should apply diff operations successfully
- should activate workflow after successful update
- should deactivate workflow after successful update

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

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

* fix: update integration tests to use minimal response format

Integration tests now verify minimal response format and use
client.getWorkflow() to fetch actual workflow state for verification.

Conceived by Romuald Czlonkowski - www.aiadvisors.pl/en

* fix: update create/update workflow integration tests for minimal response

Integration tests now verify minimal response and use client.getWorkflow()
to fetch actual workflow state for detailed verification.

Conceived by Romuald Czlonkowski - www.aiadvisors.pl/en

* fix: add type assertions to fix TypeScript errors in tests

Conceived by Romuald Czlonkowski - www.aiadvisors.pl/en

---------

Co-authored-by: Romuald Członkowski <romualdczlonkowski@MacBook-Pro-Romuald.local>
Co-authored-by: Claude <noreply@anthropic.com>

src/mcp/handlers-n8n-manager.ts

@@ -518,8 +518,13 @@ export async function handleCreateWorkflow(args: unknown, context?: InstanceCont
 
     return {
       success: true,
-      data: workflow,
-      message: `Workflow "${workflow.name}" created successfully with ID: ${workflow.id}`
+      data: {
+        id: workflow.id,
+        name: workflow.name,
+        active: workflow.active,
+        nodeCount: workflow.nodes?.length || 0
+      },
+      message: `Workflow "${workflow.name}" created successfully with ID: ${workflow.id}. Use n8n_get_workflow with mode 'structure' to verify current state.`
     };
   } catch (error) {
     if (error instanceof z.ZodError) {
@@ -813,8 +818,13 @@ export async function handleUpdateWorkflow(
 
     return {
       success: true,
-      data: workflow,
-      message: `Workflow "${workflow.name}" updated successfully`
+      data: {
+        id: workflow.id,
+        name: workflow.name,
+        active: workflow.active,
+        nodeCount: workflow.nodes?.length || 0
+      },
+      message: `Workflow "${workflow.name}" updated successfully. Use n8n_get_workflow with mode 'structure' to verify current state.`
     };
   } catch (error) {
     // Track failed mutation
@@ -880,8 +890,12 @@ export async function handleDeleteWorkflow(args: unknown, context?: InstanceCont
 
     return {
       success: true,
-      data: deleted,
-      message: `Workflow ${id} deleted successfully`
+      data: {
+        id: deleted?.id || id,
+        name: deleted?.name,
+        deleted: true
+      },
+      message: `Workflow "${deleted?.name || id}" deleted successfully.`
     };
   } catch (error) {
     if (error instanceof z.ZodError) {