feat: setup docker, backend, and gitea pipeline for production

Dockerfile

@@ -0,0 +1,37 @@
+# Stage 1: Build Frontend
+FROM node:22-alpine AS builder
+
+WORKDIR /app
+
+COPY package.json ./
+# In a real scenario, copy package-lock.json too
+# COPY package-lock.json ./
+
+RUN npm install
+
+COPY . .
+
+RUN npm run build
+
+# Stage 2: Production Runtime
+FROM node:22-alpine
+
+WORKDIR /app
+
+ENV NODE_ENV=production
+
+COPY package.json ./
+COPY backend/package.json ./backend/
+
+# Install dependencies (including production deps for backend)
+RUN npm install --omit=dev
+
+# Copy backend source
+COPY backend/ ./backend/
+
+# Copy built frontend from builder stage
+COPY --from=builder /app/dist ./dist
+
+EXPOSE 3001
+
+CMD ["node", "backend/index.js"]