feat: add ESLint configuration and testing infrastructure

Add comprehensive ESLint setup with React and TypeScript support, create basic integration tests for the shutdown utilities, and enhance the Justfile with a new check command that runs all validation steps (cargo check, clippy, tests, and linting).

web/tsconfig.json

@@ -11,6 +11,7 @@
     "moduleResolution": "bundler",
     "allowImportingTsExtensions": true,
     "verbatimModuleSyntax": true,
+    "isolatedModules": true,
     "noEmit": true,
 
     /* Linting */