Patch container CVEs: Next 14.2.35, Go 1.25 + pgx 5.10, alpine 3.22, npm stripped

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

backend/Dockerfile

@@ -1,5 +1,5 @@
 # Build stage
-FROM golang:1.24-alpine AS builder
+FROM golang:1.25-alpine AS builder
 
 WORKDIR /app
 
@@ -17,7 +17,7 @@ COPY . .
 RUN CGO_ENABLED=0 GOOS=linux go build -ldflags="-w -s" -o /api ./cmd/api
 
 # Final stage
-FROM alpine:3.19
+FROM alpine:3.22
 
 WORKDIR /app