feat: implement core figlet converter with live preview

Implemented Phases 2-4 of the implementation plan:

**Phase 2: Font Management System**
- Created font loading service with caching
- Added API route to list all 373 figlet fonts
- Implemented font metadata types

**Phase 3: Core Figlet Engine**
- Built figlet.js wrapper service for ASCII art generation
- Added async/sync rendering methods
- Implemented debounced text updates (300ms)
- Created utility functions (cn, debounce)

**Phase 4: Main UI Components**
- Built reusable UI primitives (Button, Input, Card)
- Created TextInput component with character counter (100 char limit)
- Implemented FontPreview with loading states
- Added FontSelector with real-time search
- Built main FigletConverter orchestrating all components

**Features Implemented:**
- Live preview with 300ms debounce
- 373 fonts from xero/figlet-fonts collection
- Fuzzy font search
- Copy to clipboard
- Download as .txt file
- Responsive 3-column layout (mobile-friendly)
- Character counter
- Loading states
- Empty states

**Tech Stack:**
- Next.js 16 App Router with Turbopack
- React 19 with client components
- TypeScript with strict types
- Tailwind CSS 4 for styling
- figlet.js for rendering
- Font caching for performance

The application is fully functional and ready for testing!

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

tsconfig.json

@@ -1,7 +1,11 @@
 {
   "compilerOptions": {
     "target": "ES2017",
-    "lib": ["dom", "dom.iterable", "esnext"],
+    "lib": [
+      "dom",
+      "dom.iterable",
+      "esnext"
+    ],
     "allowJs": true,
     "skipLibCheck": true,
     "strict": true,
@@ -11,7 +15,7 @@
     "moduleResolution": "bundler",
     "resolveJsonModule": true,
     "isolatedModules": true,
-    "jsx": "preserve",
+    "jsx": "react-jsx",
     "incremental": true,
     "plugins": [
       {
@@ -19,9 +23,19 @@
       }
     ],
     "paths": {
-      "@/*": ["./*"]
+      "@/*": [
+        "./*"
+      ]
     }
   },
-  "include": ["next-env.d.ts", "**/*.ts", "**/*.tsx", ".next/types/**/*.ts"],
-  "exclude": ["node_modules"]
+  "include": [
+    "next-env.d.ts",
+    "**/*.ts",
+    "**/*.tsx",
+    ".next/types/**/*.ts",
+    ".next/dev/types/**/*.ts"
+  ],
+  "exclude": [
+    "node_modules"
+  ]
 }