Fix Dockerfile: add DATABASE_URL for Prisma build

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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Dockerfile

@@ -10,6 +10,9 @@ COPY package.json package-lock.json* ./
 COPY prisma ./prisma/
 RUN npm ci
 
+# Set dummy DATABASE_URL for Prisma client generation
+ENV DATABASE_URL="file:./placeholder.db"
+
 # Generate Prisma client
 RUN npx prisma generate
 
@@ -19,6 +22,9 @@ WORKDIR /app
 COPY --from=deps /app/node_modules ./node_modules
 COPY . .
 
+# Set dummy DATABASE_URL for Prisma client generation (actual URL provided at runtime)
+ENV DATABASE_URL="file:./placeholder.db"
+
 # Generate Prisma client in builder
 RUN npx prisma generate