fix: fix PWA for mobile

frontend/Dockerfile

@@ -1,10 +1,18 @@
-FROM node:22-alpine AS builder
+FROM node:22 AS builder
+
+RUN apt-get update && apt-get install -y --no-install-recommends librsvg2-bin && rm -rf /var/lib/apt/lists/*
 
 WORKDIR /app
 COPY package.json package-lock.json* ./
 RUN npm ci
 
 COPY . .
+
+# Generate PNG icons from SVG source
+RUN mkdir -p public/icons && \
+    rsvg-convert -w 192 -h 192 public/icon-source.svg -o public/icons/icon-192.png && \
+    rsvg-convert -w 512 -h 512 public/icon-source.svg -o public/icons/icon-512.png
+
 RUN npm run build
 
 FROM nginx:alpine

frontend/public/icon-source.svg

@@ -0,0 +1,13 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512">
+  <!-- Background -->
+  <rect width="512" height="512" rx="96" fill="#0f172a"/>
+  <!-- Chart line scaled to center safe zone (~360px) -->
+  <g transform="translate(76, 76) scale(15)">
+    <polyline points="22 7 13.5 15.5 8.5 10.5 2 17"
+      fill="none" stroke="#3b82f6" stroke-width="2.2"
+      stroke-linecap="round" stroke-linejoin="round"/>
+    <polyline points="16 7 22 7 22 13"
+      fill="none" stroke="#3b82f6" stroke-width="2.2"
+      stroke-linecap="round" stroke-linejoin="round"/>
+  </g>
+</svg>

frontend/vite.config.ts

@@ -16,9 +16,10 @@ export default defineConfig({
         theme_color: '#0f172a',
         background_color: '#0f172a',
         display: 'standalone',
+        start_url: '/',
         icons: [
-          { src: '/icons/icon-192.png', sizes: '192x192', type: 'image/png' },
-          { src: '/icons/icon-512.png', sizes: '512x512', type: 'image/png' },
+          { src: '/icons/icon-192.png', sizes: '192x192', type: 'image/png', purpose: 'any' },
+          { src: '/icons/icon-512.png', sizes: '512x512', type: 'image/png', purpose: 'any maskable' },
         ],
       },
       workbox: {