feat: enhanced authentication logging for better debugging (fixes #22, #16)

- Added specific error reasons for auth failures: no_auth_header, invalid_auth_format, invalid_token
- Fixed AUTH_TOKEN_FILE support in Docker production stacks (issue #16)
- Added AUTH_TOKEN_FILE support to single-session HTTP server for consistency
- Enhanced security by removing token lengths from logs
- Added token trimming and empty token validation
- Updated Docker entrypoint to properly support AUTH_TOKEN_FILE
- Bumped version to 2.7.10

This improves debugging for mcp-remote authentication issues and enables
proper Docker secrets usage in production environments.

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

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

package.runtime.json

@@ -1,6 +1,6 @@
 {
   "name": "n8n-mcp-runtime",
-  "version": "2.7.9",
+  "version": "2.7.10",
   "description": "n8n MCP Server Runtime Dependencies Only",
   "private": true,
   "dependencies": {