feat: Refactor service management scripts to use a unified dev script

- Added package.json to manage development scripts.
- Updated restart-services.ps1 to call the new dev script for starting services.
- Refactored start-admin.ps1, start-backend.ps1, start-frontend.ps1, and start-mcp.ps1 to utilize the dev script for starting respective services.
- Enhanced stop-services.ps1 to improve process termination logic by matching command patterns.

backend/Cargo.lock

@@ -5731,6 +5731,7 @@ dependencies = [
  "async-trait",
  "axum",
  "axum-extra",
+ "base64 0.22.1",
  "chrono",
  "fastembed",
  "fluent-templates",