Performance optimizations, logic decoupling, and stricter CI pipeline

.github/workflows/ci.yml

@@ -0,0 +1,58 @@
+name: CI
+
+on:
+  push:
+    branches: ["main"]
+  pull_request:
+    branches: ["main"]
+
+jobs:
+  build-and-test:
+    name: Build, Lint, and Test
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: ./frontend
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Setup Bun
+        uses: oven-sh/setup-bun@v2
+        with:
+          bun-version: latest
+
+      # Cache Bun dependencies
+      - name: Cache Bun dependencies
+        uses: actions/cache@v4
+        with:
+          path: ~/.bun/install/cache
+          key: ${{ runner.os }}-bun-${{ hashFiles('**/bun.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-bun-
+
+      # Cache Next.js build
+      - name: Cache Next.js build
+        uses: actions/cache@v4
+        with:
+          path: |
+            frontend/.next/cache
+          key: ${{ runner.os }}-nextjs-${{ hashFiles('**/bun.lock') }}-${{ hashFiles('frontend/src/**/*.[jt]s', 'frontend/src/**/*.[jt]sx') }}
+          restore-keys: |
+            ${{ runner.os }}-nextjs-${{ hashFiles('**/bun.lock') }}-
+
+      - name: Install dependencies
+        run: bun install --frozen-lockfile
+
+      - name: Lint (ESLint 9)
+        run: bun run lint
+
+      - name: Type Check (TypeScript)
+        run: bun run type-check
+
+      - name: Run Tests
+        run: bun run test
+
+      - name: Build Project
+        run: bun run build

frontend/eslint.config.mjs

@@ -0,0 +1,73 @@
+import js from "@eslint/js";
+import path from "path";
+import { fileURLToPath } from "url";
+import tseslint from "typescript-eslint";
+import nextPlugin from "@next/eslint-plugin-next";
+import reactPlugin from "eslint-plugin-react";
+import globals from "globals";
+import { FlatCompat } from "@eslint/eslintrc";
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
+const compat = new FlatCompat({
+  baseDirectory: __dirname,
+});
+
+export default tseslint.config(
+  {
+    ignores: [
+      "**/node_modules/**",
+      "**/.next/**",
+      "**/out/**",
+      "**/build/**",
+      "eslint.config.mjs",
+    ],
+  },
+  js.configs.recommended,
+  ...tseslint.configs.recommended,
+  // Use compat for react-hooks to ensure legacy plugin structure is handled correctly
+  ...compat.plugins("eslint-plugin-react-hooks"),
+  {
+    files: ["**/*.ts", "**/*.tsx", "**/*.js", "**/*.jsx"],
+    plugins: {
+      "@next/next": nextPlugin,
+      react: reactPlugin,
+    },
+    languageOptions: {
+      globals: {
+        ...globals.browser,
+        ...globals.node,
+      },
+      parserOptions: {
+        ecmaFeatures: {
+          jsx: true,
+        },
+      },
+    },
+    settings: {
+      react: {
+        version: "detect",
+      },
+    },
+    rules: {
+      ...reactPlugin.configs.recommended.rules,
+      // Enable hooks rules manually since we loaded the plugin via compat
+      "react-hooks/rules-of-hooks": "error",
+      "react-hooks/exhaustive-deps": "warn",
+
+      // Essential Next.js Rules (Manual)
+      "@next/next/no-html-link-for-pages": "error",
+      "@next/next/no-img-element": "error",
+      "@next/next/no-sync-scripts": "error",
+
+      // Custom & Relaxed Rules
+      "react/react-in-jsx-scope": "off",
+      "react/prop-types": "off",
+      "@typescript-eslint/no-unused-vars": "warn",
+      "@typescript-eslint/no-explicit-any": "warn",
+      "@typescript-eslint/no-require-imports": "warn",
+      "react/no-unknown-property": "warn",
+    },
+  },
+);

frontend/package.json

@@ -7,7 +7,8 @@
     "dev": "bun --bun next dev --turbo",
     "build": "bun --bun next build",
     "start": "bun --bun next start",
-    "lint": "tsc --noEmit",
+    "lint": "eslint .",
+    "type-check": "tsc --noEmit",
     "test": "bun test",
     "test:watch": "bun test --watch",
     "test:coverage": "bun test --coverage"
@@ -35,13 +36,14 @@
     "@types/react": "^19.2.7",
     "@types/react-dom": "^19.2.3",
     "@typescript-eslint/eslint-plugin": "^8.50.0",
-    "@typescript-eslint/parser": "^8.50.0",
-    "autoprefixer": "^10.4.23",
+    "globals": "^16.5.0",
+    "typescript-eslint": "^8.50.0",
+    "@eslint/js": "^9.39.2",
+    "@next/eslint-plugin-next": "^16.0.10",
     "eslint": "^9.39.2",
-    "eslint-config-next": "^16.0.10",
     "eslint-plugin-react": "^7.37.5",
     "postcss": "^8.5.6",
-    "tailwindcss": "3.4.17",
+    "tailwindcss": "^3.4.19",
     "typescript": "^5.9.3"
   }
 }