chore: update MCP SDK from 1.27.1 to 1.28.0

- Pinned @modelcontextprotocol/sdk to 1.28.0 (was ^1.27.1)
- Updated CI dependency check to expect 1.28.0
- SDK 1.28.0 includes: loopback port relaxation, inputSchema fix,
  timeout cleanup fix, OAuth scope improvements
- All 15 MCP tool tests pass with no regressions

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

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

package-lock.json

@@ -1,15 +1,15 @@
 {
   "name": "n8n-mcp",
-  "version": "2.40.5",
+  "version": "2.41.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "n8n-mcp",
-      "version": "2.40.5",
+      "version": "2.41.0",
       "license": "MIT",
       "dependencies": {
-        "@modelcontextprotocol/sdk": "^1.27.1",
+        "@modelcontextprotocol/sdk": "1.28.0",
         "@n8n/n8n-nodes-langchain": "^2.13.1",
         "@supabase/supabase-js": "^2.57.4",
         "dotenv": "^16.5.0",
@@ -7690,9 +7690,9 @@
       "license": "BSD-2-Clause"
     },
     "node_modules/@modelcontextprotocol/sdk": {
-      "version": "1.27.1",
-      "resolved": "https://registry.npmjs.org/@modelcontextprotocol/sdk/-/sdk-1.27.1.tgz",
-      "integrity": "sha512-sr6GbP+4edBwFndLbM60gf07z0FQ79gaExpnsjMGePXqFcSSb7t6iscpjk9DhFhwd+mTEQrzNafGP8/iGGFYaA==",
+      "version": "1.28.0",
+      "resolved": "https://registry.npmjs.org/@modelcontextprotocol/sdk/-/sdk-1.28.0.tgz",
+      "integrity": "sha512-gmloF+i+flI8ouQK7MWW4mOwuMh4RePBuPFAEPC6+pdqyWOUMDOixb6qZ69owLJpz6XmyllCouc4t8YWO+E2Nw==",
       "license": "MIT",
       "dependencies": {
         "@hono/node-server": "^1.19.9",