Use pre-built dist folder instead of building in Docker

Skip vite build step entirely - use pre-built frontend dist folder.
HF Space's git clone resolves LFS files properly, so the ONNX models
and WASM files should be copied correctly.

This avoids the vite build failures we've been seeing.

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

Dockerfile

@@ -3,7 +3,7 @@ FROM node:20-slim
 # Set noninteractive installation
 ENV DEBIAN_FRONTEND=noninteractive
 
-# Build timestamp to force cache invalidation: 2026-01-12T21:50
+# Build timestamp to force cache invalidation: 2026-01-12T22:15
 
 # Install build dependencies
 RUN apt-get update && apt-get install -y \
@@ -14,18 +14,10 @@ RUN apt-get update && apt-get install -y \
 # Create app directory
 WORKDIR /app
 
-# Copy only the source files (not pre-built dist)
+# Copy package files first for better caching
 COPY trigo-web/package*.json ./
 COPY trigo-web/app/package*.json ./app/
 COPY trigo-web/backend/package*.json ./backend/
-COPY trigo-web/inc/ ./inc/
-COPY trigo-web/public/ ./public/
-COPY trigo-web/app/src/ ./app/src/
-COPY trigo-web/app/index.html ./app/
-COPY trigo-web/app/vite.config.ts ./app/
-COPY trigo-web/app/tsconfig*.json ./app/
-COPY trigo-web/backend/src/ ./backend/src/
-COPY trigo-web/backend/tsconfig.json ./backend/
 
 # Copy .env files
 COPY trigo-web/.env* ./
@@ -35,16 +27,27 @@ COPY trigo-web/backend/.env* ./backend/
 # Install build tools globally
 RUN npm install -g tsx jison typescript esbuild
 
-# Install dependencies
-RUN npm install --omit=dev && \
-    cd app && npm install && \
-    cd ../backend && npm install && \
-    cd ..
+# Install production dependencies only at root level
+RUN npm install --omit=dev
+
+# Install app runtime dependencies (for onnxruntime-web)
+RUN cd app && npm install --omit=dev
+
+# Install backend dependencies
+RUN cd backend && npm install
 
-# Build frontend with vite (increase memory limit)
-RUN cd app && NODE_OPTIONS="--max-old-space-size=4096" npm run build:prod
+# Copy pre-built frontend dist folder (includes ONNX models and WASM files via LFS)
+COPY trigo-web/app/dist/ ./app/dist/
 
-# Build backend with esbuild
+# Copy public folder
+COPY trigo-web/public/ ./public/
+
+# Copy inc folder (shared types)
+COPY trigo-web/inc/ ./inc/
+
+# Copy backend source and build with esbuild
+COPY trigo-web/backend/src/ ./backend/src/
+COPY trigo-web/backend/tsconfig.json ./backend/
 RUN mkdir -p backend/dist/backend/src && \
     esbuild backend/src/server.ts --bundle --platform=node --target=node20 --format=esm --outfile=backend/dist/backend/src/server.js --external:express --external:socket.io --external:cors --external:dotenv --external:uuid