fix(frontend): hardcode build-time placeholder ENVs for AUTH_URL/SECRET

cannamanage-frontend/Dockerfile

@@ -12,19 +12,14 @@ COPY --from=deps /app/node_modules ./node_modules
 COPY . .
 
 ENV NEXT_TELEMETRY_DISABLED=1
-# Provide placeholder build-time values so Next.js SSG doesn't crash on undefined URLs
+# Hardcoded build-time placeholders — NextAuth v5 reads AUTH_URL at module init time.
 # Real values are injected at runtime via docker-compose environment.
-# NextAuth v5 uses AUTH_URL (not NEXTAUTH_URL) as its canonical base URL.
-ARG NEXTAUTH_URL=http://localhost:3000
-ARG AUTH_URL=http://localhost:3000
-ARG NEXTAUTH_SECRET=build-time-placeholder-secret-minimum-32-chars
-ARG AUTH_SECRET=build-time-placeholder-secret-minimum-32-chars
-ARG BACKEND_URL=http://localhost:8080
-ENV NEXTAUTH_URL=${NEXTAUTH_URL}
-ENV AUTH_URL=${AUTH_URL}
-ENV NEXTAUTH_SECRET=${NEXTAUTH_SECRET}
-ENV AUTH_SECRET=${AUTH_SECRET}
-ENV BACKEND_URL=${BACKEND_URL}
+ENV AUTH_URL=http://localhost:3000
+ENV NEXTAUTH_URL=http://localhost:3000
+ENV AUTH_SECRET=build-time-placeholder-secret-minimum-32-characters
+ENV NEXTAUTH_SECRET=build-time-placeholder-secret-minimum-32-characters
+ENV AUTH_TRUST_HOST=1
+ENV BACKEND_URL=http://localhost:8080
 RUN pnpm build
 
 FROM base AS runner