feat: generate PWA icons and assets (#33)

- Create icon.svg with pantry shelves design
- Generate icon-192x192.png and icon-512x512.png
- Generate maskable variants for better Android support
- Create favicon.ico and apple-touch-icon.png
- Generate placeholder screenshots (mobile + desktop)
- Add icon generation scripts using sharp
- Add npm script for easy regeneration

Icon design features:
- Emerald gradient background (#10b981)
- Pantry shelves with jars, boxes, and cans
- Clean, recognizable silhouette
- Works at all sizes

Closes #33

app/nuxt.config.ts

@@ -5,7 +5,8 @@ export default defineNuxtConfig({
 
   modules: [
     '@nuxt/ui',
-    '@nuxt/fonts'
+    '@nuxt/fonts',
+    '@vite-pwa/nuxt'
   ],
 
   runtimeConfig: {
@@ -17,5 +18,102 @@ export default defineNuxtConfig({
 
   colorMode: {
     preference: 'light'
+  },
+
+  pwa: {
+    registerType: 'autoUpdate',
+    manifest: {
+      name: 'Pantry - Smart Inventory Manager',
+      short_name: 'Pantry',
+      description: 'Track your household pantry inventory with ease. Barcode scanning, smart organization, and multi-user support.',
+      theme_color: '#10b981',
+      background_color: '#ffffff',
+      display: 'standalone',
+      orientation: 'portrait',
+      scope: '/',
+      start_url: '/',
+      categories: ['productivity', 'lifestyle'],
+      icons: [
+        {
+          src: '/icon-192x192.png',
+          sizes: '192x192',
+          type: 'image/png',
+          purpose: 'any'
+        },
+        {
+          src: '/icon-512x512.png',
+          sizes: '512x512',
+          type: 'image/png',
+          purpose: 'any'
+        },
+        {
+          src: '/icon-192x192-maskable.png',
+          sizes: '192x192',
+          type: 'image/png',
+          purpose: 'maskable'
+        },
+        {
+          src: '/icon-512x512-maskable.png',
+          sizes: '512x512',
+          type: 'image/png',
+          purpose: 'maskable'
+        }
+      ],
+      screenshots: [
+        {
+          src: '/screenshot-mobile.png',
+          sizes: '390x844',
+          type: 'image/png',
+          form_factor: 'narrow',
+          label: 'Pantry inventory view on mobile'
+        },
+        {
+          src: '/screenshot-desktop.png',
+          sizes: '1920x1080',
+          type: 'image/png',
+          form_factor: 'wide',
+          label: 'Pantry inventory view on desktop'
+        }
+      ]
+    },
+    workbox: {
+      navigateFallback: '/',
+      globPatterns: ['**/*.{js,css,html,png,svg,ico}'],
+      cleanupOutdatedCaches: true,
+      runtimeCaching: [
+        {
+          urlPattern: /^https:\/\/api\.supabase\.co\/.*/i,
+          handler: 'NetworkFirst',
+          options: {
+            cacheName: 'supabase-api',
+            expiration: {
+              maxEntries: 100,
+              maxAgeSeconds: 60 * 60 * 24 // 24 hours
+            },
+            cacheableResponse: {
+              statuses: [0, 200]
+            }
+          }
+        },
+        {
+          urlPattern: /^https:\/\/.*\.supabase\.co\/.*/i,
+          handler: 'NetworkFirst',
+          options: {
+            cacheName: 'supabase-data',
+            expiration: {
+              maxEntries: 100,
+              maxAgeSeconds: 60 * 60 * 24 // 24 hours
+            },
+            cacheableResponse: {
+              statuses: [0, 200]
+            }
+          }
+        }
+      ]
+    },
+    devOptions: {
+      enabled: true,
+      type: 'module'
+    }
   }
 })

app/package.json

@@ -7,7 +7,8 @@
     "dev": "nuxt dev",
     "generate": "nuxt generate",
     "preview": "nuxt preview",
-    "postinstall": "nuxt prepare"
+    "postinstall": "nuxt prepare",
+    "generate:icons": "node scripts/generate-icons.js && node scripts/generate-screenshots.js"
   },
   "dependencies": {
     "@nuxt/fonts": "^0.13.0",
@@ -19,6 +20,8 @@
     "vue-router": "^4.6.4"
   },
   "devDependencies": {
-    "@nuxtjs/tailwindcss": "^6.14.0"
+    "@nuxtjs/tailwindcss": "^6.14.0",
+    "@vite-pwa/nuxt": "^1.1.1",
+    "sharp": "^0.34.5"
   }
 }

app/public/icon.svg

@@ -0,0 +1,46 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" fill="none">
+  <!-- Background circle with emerald gradient -->
+  <defs>
+    <linearGradient id="grad" x1="0%" y1="0%" x2="100%" y2="100%">
+      <stop offset="0%" style="stop-color:#10b981;stop-opacity:1" />
+      <stop offset="100%" style="stop-color:#059669;stop-opacity:1" />
+    </linearGradient>
+  </defs>
+  
+  <!-- Background -->
+  <circle cx="256" cy="256" r="256" fill="url(#grad)"/>
+  
+  <!-- Pantry shelves icon (simplified cabinet with items) -->
+  <g transform="translate(106, 96)">
+    <!-- Cabinet outline -->
+    <rect x="0" y="0" width="300" height="320" rx="12" fill="none" stroke="white" stroke-width="8"/>
+    
+    <!-- Top shelf -->
+    <line x1="0" y1="80" x2="300" y2="80" stroke="white" stroke-width="6"/>
+    
+    <!-- Middle shelf -->
+    <line x1="0" y1="160" x2="300" y2="160" stroke="white" stroke-width="6"/>
+    
+    <!-- Bottom shelf -->
+    <line x1="0" y1="240" x2="300" y2="240" stroke="white" stroke-width="6"/>
+    
+    <!-- Top shelf items - jars -->
+    <circle cx="60" cy="40" r="25" fill="white" opacity="0.9"/>
+    <circle cx="150" cy="40" r="25" fill="white" opacity="0.9"/>
+    <circle cx="240" cy="40" r="25" fill="white" opacity="0.9"/>
+    
+    <!-- Middle shelf items - boxes -->
+    <rect x="35" y="105" width="50" height="40" rx="4" fill="white" opacity="0.9"/>
+    <rect x="125" y="105" width="50" height="40" rx="4" fill="white" opacity="0.9"/>
+    <rect x="215" y="105" width="50" height="40" rx="4" fill="white" opacity="0.9"/>
+    
+    <!-- Bottom shelf items - cans -->
+    <rect x="35" y="185" width="50" height="45" rx="6" fill="white" opacity="0.9"/>
+    <rect x="125" y="185" width="50" height="45" rx="6" fill="white" opacity="0.9"/>
+    <rect x="215" y="185" width="50" height="45" rx="6" fill="white" opacity="0.9"/>
+    
+    <!-- Very bottom items - larger containers -->
+    <rect x="45" y="260" width="70" height="50" rx="6" fill="white" opacity="0.9"/>
+    <rect x="185" y="260" width="70" height="50" rx="6" fill="white" opacity="0.9"/>
+  </g>
+</svg>

app/scripts/generate-icons.js

@@ -0,0 +1,70 @@
+#!/usr/bin/env node
+import { readFile, writeFile } from 'fs/promises';
+import { join, dirname } from 'path';
+import { fileURLToPath } from 'url';
+import sharp from 'sharp';
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+const publicDir = join(__dirname, '..', 'public');
+const svgPath = join(publicDir, 'icon.svg');
+
+const sizes = [
+  { size: 192, name: 'icon-192x192.png', maskable: false },
+  { size: 512, name: 'icon-512x512.png', maskable: false },
+  { size: 192, name: 'icon-192x192-maskable.png', maskable: true },
+  { size: 512, name: 'icon-512x512-maskable.png', maskable: true },
+];
+
+async function generateIcons() {
+  console.log('Reading SVG icon...');
+  const svgBuffer = await readFile(svgPath);
+  
+  for (const { size, name, maskable } of sizes) {
+    console.log(`Generating ${name}...`);
+    
+    let buffer;
+    if (maskable) {
+      // Maskable icons need safe zone padding (80% of icon in center)
+      // Create a transparent canvas with padding
+      const paddedSize = size;
+      const iconSize = Math.floor(size * 0.8);
+      const offset = Math.floor((paddedSize - iconSize) / 2);
+      
+      // Resize SVG to icon size
+      const iconBuffer = await sharp(svgBuffer)
+        .resize(iconSize, iconSize)
+        .png()
+        .toBuffer();
+      
+      // Create transparent background and composite
+      buffer = await sharp({
+        create: {
+          width: paddedSize,
+          height: paddedSize,
+          channels: 4,
+          background: { r: 0, g: 0, b: 0, alpha: 0 }
+        }
+      })
+        .composite([{
+          input: iconBuffer,
+          top: offset,
+          left: offset
+        }])
+        .png()
+        .toBuffer();
+    } else {
+      // Regular icon - full size
+      buffer = await sharp(svgBuffer)
+        .resize(size, size)
+        .png()
+        .toBuffer();
+    }
+    
+    await writeFile(join(publicDir, name), buffer);
+    console.log(`✓ ${name}`);
+  }
+  
+  console.log('\n✅ All icons generated successfully!');
+}
+
+generateIcons().catch(console.error);

app/scripts/generate-screenshots.js

@@ -0,0 +1,124 @@
+#!/usr/bin/env node
+import { writeFile } from 'fs/promises';
+import { join, dirname } from 'path';
+import { fileURLToPath } from 'url';
+import sharp from 'sharp';
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+const publicDir = join(__dirname, '..', 'public');
+
+async function generateScreenshots() {
+  // Mobile screenshot (390x844 - iPhone 12/13/14 size)
+  console.log('Generating mobile screenshot placeholder...');
+  const mobileBuffer = await sharp({
+    create: {
+      width: 390,
+      height: 844,
+      channels: 4,
+      background: { r: 249, g: 250, b: 251, alpha: 1 } // Tailwind gray-50
+    }
+  })
+    .composite([
+      {
+        input: Buffer.from(`
+          <svg width="390" height="844">
+            <!-- Header -->
+            <rect width="390" height="64" fill="#10b981"/>
+            <text x="195" y="42" font-family="Arial" font-size="20" fill="white" text-anchor="middle" font-weight="bold">Pantry</text>
+            
+            <!-- Content area -->
+            <text x="24" y="104" font-family="Arial" font-size="24" fill="#111827" font-weight="bold">My Pantry</text>
+            
+            <!-- Item cards -->
+            <rect x="16" y="130" width="358" height="80" rx="8" fill="white" stroke="#e5e7eb" stroke-width="1"/>
+            <text x="32" y="160" font-family="Arial" font-size="16" fill="#111827" font-weight="600">Milk</text>
+            <text x="32" y="185" font-family="Arial" font-size="14" fill="#6b7280">Fridge • 1L</text>
+            
+            <rect x="16" y="226" width="358" height="80" rx="8" fill="white" stroke="#e5e7eb" stroke-width="1"/>
+            <text x="32" y="256" font-family="Arial" font-size="16" fill="#111827" font-weight="600">Pasta</text>
+            <text x="32" y="281" font-family="Arial" font-size="14" fill="#6b7280">Pantry • 500g</text>
+            
+            <rect x="16" y="322" width="358" height="80" rx="8" fill="white" stroke="#e5e7eb" stroke-width="1"/>
+            <text x="32" y="352" font-family="Arial" font-size="16" fill="#111827" font-weight="600">Tomato Sauce</text>
+            <text x="32" y="377" font-family="Arial" font-size="14" fill="#6b7280">Pantry • 400ml</text>
+            
+            <!-- Bottom navigation -->
+            <rect y="780" width="390" height="64" fill="white" stroke="#e5e7eb" stroke-width="1"/>
+            <text x="78" y="820" font-family="Arial" font-size="12" fill="#6b7280" text-anchor="middle">Home</text>
+            <text x="195" y="820" font-family="Arial" font-size="12" fill="#10b981" text-anchor="middle">Scan</text>
+            <text x="312" y="820" font-family="Arial" font-size="12" fill="#6b7280" text-anchor="middle">Settings</text>
+          </svg>
+        `),
+        top: 0,
+        left: 0
+      }
+    ])
+    .png()
+    .toBuffer();
+  
+  await writeFile(join(publicDir, 'screenshot-mobile.png'), mobileBuffer);
+  console.log('✓ screenshot-mobile.png');
+  
+  // Desktop screenshot (1920x1080)
+  console.log('Generating desktop screenshot placeholder...');
+  const desktopBuffer = await sharp({
+    create: {
+      width: 1920,
+      height: 1080,
+      channels: 4,
+      background: { r: 249, g: 250, b: 251, alpha: 1 } // Tailwind gray-50
+    }
+  })
+    .composite([
+      {
+        input: Buffer.from(`
+          <svg width="1920" height="1080">
+            <!-- Header -->
+            <rect width="1920" height="80" fill="#10b981"/>
+            <text x="960" y="50" font-family="Arial" font-size="32" fill="white" text-anchor="middle" font-weight="bold">Pantry - Smart Inventory Manager</text>
+            
+            <!-- Sidebar -->
+            <rect x="0" y="80" width="280" height="1000" fill="white" stroke="#e5e7eb" stroke-width="1"/>
+            <text x="32" y="130" font-family="Arial" font-size="18" fill="#10b981" font-weight="600">Dashboard</text>
+            <text x="32" y="180" font-family="Arial" font-size="18" fill="#6b7280">Scan Item</text>
+            <text x="32" y="230" font-family="Arial" font-size="18" fill="#6b7280">Settings</text>
+            
+            <!-- Main content -->
+            <text x="340" y="150" font-family="Arial" font-size="36" fill="#111827" font-weight="bold">My Pantry Items</text>
+            
+            <!-- Grid of items -->
+            <rect x="340" y="200" width="480" height="180" rx="12" fill="white" stroke="#e5e7eb" stroke-width="2"/>
+            <text x="370" y="250" font-family="Arial" font-size="24" fill="#111827" font-weight="600">Milk</text>
+            <text x="370" y="290" font-family="Arial" font-size="18" fill="#6b7280">Fridge • 1L • Expires in 5 days</text>
+            
+            <rect x="860" y="200" width="480" height="180" rx="12" fill="white" stroke="#e5e7eb" stroke-width="2"/>
+            <text x="890" y="250" font-family="Arial" font-size="24" fill="#111827" font-weight="600">Pasta</text>
+            <text x="890" y="290" font-family="Arial" font-size="18" fill="#6b7280">Pantry • 500g</text>
+            
+            <rect x="1380" y="200" width="480" height="180" rx="12" fill="white" stroke="#e5e7eb" stroke-width="2"/>
+            <text x="1410" y="250" font-family="Arial" font-size="24" fill="#111827" font-weight="600">Tomato Sauce</text>
+            <text x="1410" y="290" font-family="Arial" font-size="18" fill="#6b7280">Pantry • 400ml</text>
+            
+            <rect x="340" y="420" width="480" height="180" rx="12" fill="white" stroke="#e5e7eb" stroke-width="2"/>
+            <text x="370" y="470" font-family="Arial" font-size="24" fill="#111827" font-weight="600">Rice</text>
+            <text x="370" y="510" font-family="Arial" font-size="18" fill="#6b7280">Pantry • 1kg</text>
+            
+            <rect x="860" y="420" width="480" height="180" rx="12" fill="white" stroke="#e5e7eb" stroke-width="2"/>
+            <text x="890" y="470" font-family="Arial" font-size="24" fill="#111827" font-weight="600">Olive Oil</text>
+            <text x="890" y="510" font-family="Arial" font-size="18" fill="#6b7280">Pantry • 750ml</text>
+          </svg>
+        `),
+        top: 0,
+        left: 0
+      }
+    ])
+    .png()
+    .toBuffer();
+  
+  await writeFile(join(publicDir, 'screenshot-desktop.png'), desktopBuffer);
+  console.log('✓ screenshot-desktop.png');
+  
+  console.log('\n✅ All screenshots generated successfully!');
+}
+
+generateScreenshots().catch(console.error);