fix: add Docker configuration file support (fixes #105)

This commit adds comprehensive support for JSON configuration files in Docker containers,
addressing the issue where the Docker image fails to start in server mode and ignores
configuration files.

## Changes

### Docker Configuration Support
- Added parse-config.js to safely parse JSON configs and export as shell variables
- Implemented secure shell quoting to prevent command injection
- Added dangerous environment variable blocking for security
- Support for all JSON data types with proper edge case handling

### Docker Server Mode Fix
- Added support for "n8n-mcp serve" command in entrypoint
- Properly transforms serve command to HTTP mode
- Fixed missing n8n-mcp binary issue in Docker image

### Security Enhancements
- POSIX-compliant shell quoting without eval
- Blocked dangerous variables (PATH, LD_PRELOAD, etc.)
- Sanitized configuration keys to prevent invalid shell variables
- Protection against shell metacharacters in values

### Testing
- Added 53 comprehensive tests for Docker configuration
- Unit tests for parsing, security, and edge cases
- Integration tests for Docker entrypoint behavior
- Security-focused tests for injection prevention

### Documentation
- Updated Docker README with config file mounting examples
- Enhanced troubleshooting guide with config file issues
- Added version bump to 2.8.2

### Additional Files
- Included deployment-engineer and technical-researcher agent files

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

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

package.json

@@ -1,6 +1,6 @@
 {
   "name": "n8n-mcp",
-  "version": "2.8.1",
+  "version": "2.8.2",
   "description": "Integration between n8n workflow automation and Model Context Protocol (MCP)",
   "main": "dist/index.js",
   "bin": {
@@ -57,6 +57,10 @@
     "test:update-partial:debug": "node dist/scripts/test-update-partial-debug.js",
     "test:issue-45-fix": "node dist/scripts/test-issue-45-fix.js",
     "test:auth-logging": "tsx scripts/test-auth-logging.ts",
+    "test:docker": "./scripts/test-docker-config.sh all",
+    "test:docker:unit": "./scripts/test-docker-config.sh unit",
+    "test:docker:integration": "./scripts/test-docker-config.sh integration",
+    "test:docker:security": "./scripts/test-docker-config.sh security",
     "sanitize:templates": "node dist/scripts/sanitize-templates.js",
     "db:rebuild": "node dist/scripts/rebuild-database.js",
     "benchmark": "vitest bench --config vitest.config.benchmark.ts",