fix: resolve Docker CI/CD and deployment documentation issues

- Create missing v2.9.1 git tag to trigger Docker builds
- Fix GitHub Actions workflow with proper environment variables
- Add comprehensive deployment documentation updates:
  * Add missing MCP_MODE=http environment variable requirement
  * Clarify Server URL must include /mcp endpoint
  * Add complete environment variables reference table
  * Update all Docker examples with proper variable configuration
  * Add version compatibility warnings for pre-built images
  * Document build-from-source as recommended approach
  * Add comprehensive troubleshooting section with common issues
  * Include systematic debugging steps and diagnostic commands
- Optimize package.runtime.json dependencies for Docker builds
- Ensure both MCP_AUTH_TOKEN and AUTH_TOKEN use same value

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

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

.github/workflows/docker-build-n8n.yml

@@ -84,9 +84,11 @@ jobs:
         run: |
           docker run --rm \
             -e N8N_MODE=true \
+            -e MCP_MODE=http \
             -e N8N_API_URL=http://localhost:5678 \
             -e N8N_API_KEY=test \
-            -e MCP_AUTH_TOKEN=test \
+            -e MCP_AUTH_TOKEN=test-token-minimum-32-chars-long \
+            -e AUTH_TOKEN=test-token-minimum-32-chars-long \
             ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest \
             node dist/index.js n8n --version
 
@@ -97,9 +99,11 @@ jobs:
             --name n8n-mcp-test \
             -p 3000:3000 \
             -e N8N_MODE=true \
+            -e MCP_MODE=http \
             -e N8N_API_URL=http://localhost:5678 \
             -e N8N_API_KEY=test \
-            -e MCP_AUTH_TOKEN=test \
+            -e MCP_AUTH_TOKEN=test-token-minimum-32-chars-long \
+            -e AUTH_TOKEN=test-token-minimum-32-chars-long \
             ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest
           
           # Wait for container to start
@@ -108,6 +112,9 @@ jobs:
           # Test health endpoint
           curl -f http://localhost:3000/health || exit 1
           
+          # Test MCP endpoint
+          curl -f http://localhost:3000/mcp || exit 1
+          
           # Cleanup
           docker stop n8n-mcp-test
           docker rm n8n-mcp-test