chore(deps): bump node from 18-alpine to 25-alpine in /docker

Bumps node from 18-alpine to 25-alpine.

---
updated-dependencies:
- dependency-name: node
  dependency-version: 25-alpine
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

docker/Dockerfile

@@ -2,7 +2,7 @@
 # Multi-stage build for optimized production image
 
 # Stage 1: Build stage
-FROM node:18-alpine AS builder
+FROM node:25-alpine AS builder
 
 WORKDIR /app
 
@@ -19,7 +19,7 @@ COPY . .
 RUN npm run build
 
 # Stage 2: Production stage
-FROM node:18-alpine AS production
+FROM node:25-alpine AS production
 
 WORKDIR /app