fix(ci): harden test determinism and dependencies

Dockerfile

@@ -4,6 +4,7 @@ RUN corepack enable && corepack prepare pnpm@10.31.0 --activate
 WORKDIR /app
 
 COPY package.json pnpm-lock.yaml pnpm-workspace.yaml ./
+COPY scripts/prepare.mjs scripts/prepare.mjs
 RUN pnpm install --frozen-lockfile --prod=false
 
 # ── Stage 2: Build ─────────────────────────────────────────