fix: use correct sha digest for base image

Ticket: WP-6774

Author: pranavjain97

Dockerfile

@@ -2,7 +2,9 @@
 
 # Build stage
 # Using node:22.1.0-alpine with OpenSSL 3.3.2+ to address CVE-2024-6119
-FROM node:22.1.0-alpine AS builder
+# Pinned to AMD64-specific SHA256 digest for supply chain security and deterministic builds
+# To update: docker pull --platform linux/amd64 node:22.1.0-alpine && docker inspect --format='{{index .RepoDigests 0}}' node:22.1.0-alpine
+FROM node:22.1.0-alpine@sha256:487dc5d5122d578e13f2231aa4ac0f63068becd921099c4c677c850df93bede8 AS builder
 
 # Set build-time variables for reproducibility
 ARG NODE_ENV=development
@@ -53,7 +55,8 @@ RUN npm run build
 
 # Production stage
 # Using node:22.1.0-alpine with OpenSSL 3.3.2+ to address CVE-2024-6119
-FROM node:22.1.0-alpine AS production
+# Pinned to AMD64-specific SHA256 digest for supply chain security and deterministic builds
+FROM node:22.1.0-alpine@sha256:487dc5d5122d578e13f2231aa4ac0f63068becd921099c4c677c850df93bede8 AS production
 
 # Declare build arguments in production stage
 ARG PORT=3081