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>

package.json

@@ -58,6 +58,10 @@
     "test:auth-logging": "tsx scripts/test-auth-logging.ts",
     "sanitize:templates": "node dist/scripts/sanitize-templates.js",
     "db:rebuild": "node dist/scripts/rebuild-database.js",
+    "benchmark": "vitest bench --config vitest.config.benchmark.ts",
+    "benchmark:watch": "vitest bench --watch --config vitest.config.benchmark.ts",
+    "benchmark:ui": "vitest bench --ui --config vitest.config.benchmark.ts",
+    "benchmark:ci": "CI=true vitest bench --run --config vitest.config.benchmark.ts",
     "db:init": "node -e \"new (require('./dist/services/sqlite-storage-service').SQLiteStorageService)(); console.log('Database initialized')\"",
     "docs:rebuild": "ts-node src/scripts/rebuild-database.ts",
     "sync:runtime-version": "node scripts/sync-runtime-version.js",
@@ -97,6 +101,7 @@
     "@types/node": "^22.15.30",
     "@types/ws": "^8.18.1",
     "@vitest/coverage-v8": "^3.2.4",
+    "@vitest/runner": "^3.2.4",
     "@vitest/ui": "^3.2.4",
     "axios-mock-adapter": "^2.1.0",
     "fishery": "^2.3.1",