feat: add token-efficient tools and fix 400 errors on write operations

Fixes #15, Fixes #18

## Token Efficiency Improvements

- list_workflows now returns summary only (id, name, active, tags, nodeCount)
  instead of full workflow JSON - prevents context overflow
- Added list_workflows_full for when complete data is needed
- activate/deactivate/execute_workflow return minimal confirmation instead of
  full workflow dump
- Added granular update tools that do server-side fetch-modify-save:
  - update_workflow_name
  - add_node
  - update_node
  - update_node_from_file (for large SQL/code)
  - remove_node
  - connect_nodes
  - disconnect_nodes
  - update_workflow_settings
- Added download_workflow to save to file without chat output
- Added upload_workflow to create from local JSON file

## Bug Fixes

- Fixed 400 "additional properties not allowed" error by stripping workflow
  to only PUT-allowed fields (name, nodes, connections, settings, staticData)
- Fixed 400 "tags is read-only" error by removing tags from update payload
- Added detailed error messages showing actual n8n API response

Bumps version to 0.11.0 with 34 tools total.

Author: stlalpha

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "@makafeli/n8n-workflow-builder",
-  "version": "0.10.3",
+  "version": "0.11.0",
   "description": "Model Context Protocol server for n8n workflow management",
   "main": "build/server.cjs",
   "module": "./src/index.ts",