fix: raise session timeout default and fix VS Code MCP compatibility (#626, #600, #611)

- #626: Raise SESSION_TIMEOUT_MINUTES default from 5 to 30 minutes.
  Complex editing sessions easily exceed 5 min between LLM calls.

- #600: Add z.preprocess(tryParseJson, ...) to operations parameter
  in n8n_update_partial_workflow. VS Code extension sends arrays as
  JSON strings.

- #611: Strip undefined values from tool args via JSON round-trip
  before Zod validation. VS Code sends explicit undefined which
  Zod's .optional() rejects.

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

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "n8n-mcp",
-  "version": "2.41.2",
+  "version": "2.41.3",
   "description": "Integration between n8n workflow automation and Model Context Protocol (MCP)",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",