feat: add comprehensive performance benchmark tracking system

- Create benchmark test suites for critical operations:
  - Node loading performance
  - Database query performance
  - Search operations performance
  - Validation performance
  - MCP tool execution performance

- Add GitHub Actions workflow for benchmark tracking:
  - Runs on push to main and PRs
  - Uses github-action-benchmark for historical tracking
  - Comments on PRs with performance results
  - Alerts on >10% performance regressions
  - Stores results in GitHub Pages

- Create benchmark infrastructure:
  - Custom Vitest benchmark configuration
  - JSON reporter for CI results
  - Result formatter for github-action-benchmark
  - Performance threshold documentation

- Add supporting utilities:
  - SQLiteStorageService for benchmark database setup
  - MCPEngine wrapper for testing MCP tools
  - Test factories for generating benchmark data
  - Enhanced NodeRepository with benchmark methods

- Document benchmark system:
  - Comprehensive benchmark guide in docs/BENCHMARKS.md
  - Performance thresholds in .github/BENCHMARK_THRESHOLDS.md
  - README for benchmarks directory
  - Integration with existing test suite

The benchmark system will help monitor performance over time and catch regressions before they reach production.

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

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

docs/CODECOV_SETUP.md

@@ -0,0 +1,113 @@
+# Codecov Setup Guide
+
+This guide explains how to set up and configure Codecov for the n8n-MCP project.
+
+## Prerequisites
+
+1. A Codecov account (sign up at https://codecov.io)
+2. Repository admin access to add the CODECOV_TOKEN secret
+
+## Setup Steps
+
+### 1. Get Your Codecov Token
+
+1. Sign in to [Codecov](https://codecov.io)
+2. Add your repository: `czlonkowski/n8n-mcp`
+3. Copy the upload token from the repository settings
+
+### 2. Add Token to GitHub Secrets
+
+1. Go to your GitHub repository settings
+2. Navigate to `Settings` → `Secrets and variables` → `Actions`
+3. Click "New repository secret"
+4. Name: `CODECOV_TOKEN`
+5. Value: Paste your Codecov token
+6. Click "Add secret"
+
+### 3. Update the Badge Token
+
+Edit the README.md file and replace `YOUR_TOKEN` in the Codecov badge with your actual token:
+
+```markdown
+[![codecov](https://codecov.io/gh/czlonkowski/n8n-mcp/graph/badge.svg?token=YOUR_ACTUAL_TOKEN)](https://codecov.io/gh/czlonkowski/n8n-mcp)
+```
+
+Note: The token in the badge URL is a read-only token and safe to commit.
+
+## Configuration Details
+
+### codecov.yml
+
+The configuration file sets:
+- **Target coverage**: 80% for both project and patch
+- **Coverage precision**: 2 decimal places
+- **Comment behavior**: Comments on all PRs with coverage changes
+- **Ignored files**: Test files, scripts, node_modules, and build outputs
+
+### GitHub Actions
+
+The workflow:
+1. Runs tests with coverage using `npm run test:coverage`
+2. Generates LCOV format coverage report
+3. Uploads to Codecov using the official action
+4. Fails the build if upload fails
+
+### Vitest Configuration
+
+Coverage settings in `vitest.config.ts`:
+- **Provider**: V8 (fast and accurate)
+- **Reporters**: text, json, html, and lcov
+- **Thresholds**: 80% lines, 80% functions, 75% branches, 80% statements
+
+## Viewing Coverage
+
+### Local Coverage
+
+```bash
+# Generate coverage report
+npm run test:coverage
+
+# View HTML report
+open coverage/index.html
+```
+
+### Online Coverage
+
+1. Visit https://codecov.io/gh/czlonkowski/n8n-mcp
+2. View detailed reports, graphs, and file-by-file coverage
+3. Check PR comments for coverage changes
+
+## Troubleshooting
+
+### Coverage Not Uploading
+
+1. Verify CODECOV_TOKEN is set in GitHub secrets
+2. Check GitHub Actions logs for errors
+3. Ensure coverage/lcov.info is generated
+
+### Badge Not Showing
+
+1. Wait a few minutes after first upload
+2. Verify the token in the badge URL is correct
+3. Check if the repository is public/private settings match
+
+### Low Coverage Areas
+
+Current areas with lower coverage that could be improved:
+- HTTP server implementations
+- MCP index files
+- Some edge cases in validators
+
+## Best Practices
+
+1. **Write tests first**: Aim for TDD when adding features
+2. **Focus on critical paths**: Prioritize testing core functionality
+3. **Mock external dependencies**: Use MSW for HTTP, mock for databases
+4. **Keep coverage realistic**: 80% is good, 100% isn't always practical
+5. **Monitor trends**: Watch coverage over time, not just absolute numbers
+
+## Resources
+
+- [Codecov Documentation](https://docs.codecov.io/)
+- [Vitest Coverage](https://vitest.dev/guide/coverage.html)
+- [GitHub Actions + Codecov](https://github.com/codecov/codecov-action)