Add SVG assets and TypeScript configuration

- Created a new SVG for the Open Graph image (og-image.svg) with a gradient background and text elements.
- Added Vercel logo SVG (vercel.svg) for deployment branding.
- Introduced a window icon SVG (window.svg) for UI representation.
- Initialized TypeScript configuration file (tsconfig.json) with strict settings and module resolution for a React project.

public/icon.svg

@@ -0,0 +1,24 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512">
+  <defs>
+    <linearGradient id="bg" x1="0%" y1="0%" x2="100%" y2="100%">
+      <stop offset="0%" style="stop-color:#3b82f6"/>
+      <stop offset="100%" style="stop-color:#2563eb"/>
+    </linearGradient>
+  </defs>
+  <rect width="512" height="512" rx="96" fill="url(#bg)"/>
+  <g transform="translate(256,256)">
+    <!-- Page -->
+    <rect x="-100" y="-140" width="200" height="260" rx="16" fill="white" opacity="0.95"/>
+    <!-- Lines -->
+    <rect x="-68" y="-96" width="136" height="8" rx="4" fill="#3b82f6" opacity="0.3"/>
+    <rect x="-68" y="-72" width="100" height="8" rx="4" fill="#3b82f6" opacity="0.25"/>
+    <rect x="-68" y="-48" width="120" height="8" rx="4" fill="#3b82f6" opacity="0.2"/>
+    <rect x="-68" y="-24" width="80" height="8" rx="4" fill="#3b82f6" opacity="0.15"/>
+    <!-- Pen -->
+    <g transform="translate(60,60) rotate(-45)">
+      <rect x="-8" y="-80" width="16" height="100" rx="3" fill="#1e40af"/>
+      <polygon points="-8,20 8,20 0,36" fill="#1e40af"/>
+      <rect x="-8" y="-80" width="16" height="14" rx="3" fill="#fbbf24"/>
+    </g>
+  </g>
+</svg>

public/manifest.json

@@ -0,0 +1,26 @@
+{
+  "name": "BlocNote — Bloc-notes Markdown en ligne",
+  "short_name": "BlocNote",
+  "description": "Bloc-notes en ligne moderne avec support Markdown, sauvegarde automatique et mode sombre.",
+  "start_url": "/",
+  "display": "standalone",
+  "orientation": "any",
+  "background_color": "#ffffff",
+  "theme_color": "#3b82f6",
+  "lang": "fr",
+  "categories": ["productivity", "utilities"],
+  "icons": [
+    {
+      "src": "/icon-192.png",
+      "sizes": "192x192",
+      "type": "image/png",
+      "purpose": "any maskable"
+    },
+    {
+      "src": "/icon-512.png",
+      "sizes": "512x512",
+      "type": "image/png",
+      "purpose": "any maskable"
+    }
+  ]
+}

public/og-image.svg

@@ -0,0 +1,28 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1200 630">
+  <defs>
+    <linearGradient id="bg" x1="0%" y1="0%" x2="100%" y2="100%">
+      <stop offset="0%" style="stop-color:#1e3a5f"/>
+      <stop offset="50%" style="stop-color:#1a1a2e"/>
+      <stop offset="100%" style="stop-color:#0f0f17"/>
+    </linearGradient>
+  </defs>
+  <rect width="1200" height="630" fill="url(#bg)"/>
+  <!-- Icon -->
+  <g transform="translate(300,200)">
+    <rect x="0" y="0" width="100" height="130" rx="12" fill="white" opacity="0.9"/>
+    <rect x="16" y="22" width="68" height="5" rx="2.5" fill="#3b82f6" opacity="0.4"/>
+    <rect x="16" y="35" width="50" height="5" rx="2.5" fill="#3b82f6" opacity="0.3"/>
+    <rect x="16" y="48" width="60" height="5" rx="2.5" fill="#3b82f6" opacity="0.25"/>
+    <rect x="16" y="61" width="40" height="5" rx="2.5" fill="#3b82f6" opacity="0.2"/>
+  </g>
+  <!-- Title -->
+  <text x="430" y="255" font-family="system-ui, -apple-system, sans-serif" font-size="64" font-weight="800" fill="white" letter-spacing="-1">BlocNote</text>
+  <!-- Subtitle -->
+  <text x="430" y="305" font-family="system-ui, -apple-system, sans-serif" font-size="22" fill="#9ca3af">Bloc-notes Markdown en ligne • Gratuit</text>
+  <!-- Features -->
+  <text x="300" y="440" font-family="system-ui, -apple-system, sans-serif" font-size="18" fill="#60a5fa">✦ Markdown</text>
+  <text x="500" y="440" font-family="system-ui, -apple-system, sans-serif" font-size="18" fill="#60a5fa">✦ Sauvegarde auto</text>
+  <text x="740" y="440" font-family="system-ui, -apple-system, sans-serif" font-size="18" fill="#60a5fa">✦ Mode sombre</text>
+  <!-- Border accent -->
+  <rect x="0" y="620" width="1200" height="10" fill="#3b82f6"/>
+</svg>