Update Dockerfile: node:20-alpine, remove bash syntax bug in ENV

Dockerfile

@@ -1,24 +1,21 @@
-FROM node:18-alpine
+FROM node:20-alpine
 
-# Build arguments - Coolify provides SOURCE_COMMIT automatically
 ARG SOURCE_COMMIT=unknown
 ARG APP_VERSION=1.0.0
 
 WORKDIR /app
 
-# Install curl for healthcheck and git for version control operations
-RUN apk add --no-cache curl git
+# Install curl for healthcheck
+RUN apk add --no-cache curl
 
 # Copy package files first for layer caching
 COPY package*.json ./
 RUN npm install --production
 
-# Copy app code (changes more often — below the cached layer)
+# Copy app code
 COPY . .
 
-# Set environment variables for runtime
-# Extract first 7 characters of SOURCE_COMMIT for short hash
-ENV GIT_COMMIT=${SOURCE_COMMIT:0:7} \
+ENV GIT_COMMIT=${SOURCE_COMMIT} \
     APP_VERSION=${APP_VERSION}
 
 EXPOSE 3000