feat: complete OpenAPI migration and add test suite

package.json

@@ -12,6 +12,8 @@
 		"check": "biome check --write .",
 		"format": "biome format --write .",
 		"gen:api": "bun scripts/generate-schema.ts && bun x openapi-typescript generated/schema.json -o generated/api.ts",
+		"test": "vitest run",
+		"test:ui": "vitest --ui",
 		"build": "bun build ./src/index.html --outdir=dist --sourcemap --target=browser --minify --define:process.env.NODE_ENV='\"production\"' --env='VITE_*'",
 		"start": "NODE_ENV=production bun src/index.ts"
 	},
@@ -50,6 +52,7 @@
 		"@types/react": "^19",
 		"@types/react-dom": "^19",
 		"@vitejs/plugin-react": "^5.1.3",
+		"@vitest/ui": "^4.0.18",
 		"concurrently": "^9.2.1",
 		"fast-glob": "^3.3.3",
 		"openapi-typescript": "^7.10.1",
@@ -58,6 +61,7 @@
 		"postcss-simple-vars": "^7.0.1",
 		"prisma": "^6.19.2",
 		"react-dev-inspector": "^2.0.1",
-		"vite": "^7.3.1"
+		"vite": "^7.3.1",
+		"vitest": "^4.0.18"
 	}
 }