fix: pin MCP SDK version in Docker build files (v2.27.1) (#456)

* fix: pin MCP SDK version in Docker build files (#454)

The Docker image 2.27.0 was missing the Zod fix from #450 because:
- package.runtime.json had @modelcontextprotocol/sdk@^1.13.2
- Dockerfile builder had @modelcontextprotocol/sdk@^1.12.1

Both now use the pinned version 1.20.1 (no caret) to match package.json.
Also pinned zod@3.24.1 in Dockerfile for consistency.

Fixes #454

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>

* chore: bump version to 2.27.1 and update CHANGELOG

- Version bump from 2.27.0 to 2.27.1
- Added CHANGELOG entry for #454 fix (Docker SDK version)
- Added missing CHANGELOG entry for 2.27.0 (n8n_deploy_template)

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>

package.runtime.json

@@ -1,10 +1,10 @@
 {
   "name": "n8n-mcp-runtime",
-  "version": "2.26.4",
+  "version": "2.27.1",
   "description": "n8n MCP Server Runtime Dependencies Only",
   "private": true,
   "dependencies": {
-    "@modelcontextprotocol/sdk": "^1.13.2",
+    "@modelcontextprotocol/sdk": "1.20.1",
     "@supabase/supabase-js": "^2.57.4",
     "express": "^5.1.0",
     "express-rate-limit": "^7.1.5",