feat: rebuild fiscal clone architecture and harden coolify deployment

backend/Dockerfile

@@ -1,14 +1,12 @@
-FROM node:20-alpine AS base
+FROM node:20-alpine
+
 WORKDIR /app
 
-# Install Bun and update npm
 RUN npm install -g bun && npm install -g npm@latest
 
-# Install dependencies
-COPY package.json bun.lockb* ./
-RUN bun install
+COPY package.json bun.lock* ./
+RUN bun install --frozen-lockfile || bun install
 
-# Copy source code
 COPY . .
 
 ENV NODE_ENV=production
@@ -16,5 +14,4 @@ ENV PORT=3001
 
 EXPOSE 3001
 
-# Run directly from TypeScript source (Bun can execute TypeScript directly)
 CMD ["bun", "run", "src/index.ts"]