Optimizer - NowStack Mobile

<objective> Improve performance and architecture in this repo without importing assumptions from the web-only NowStack SaaS app. NowStack Mobile has three surfaces:

• convex/ for the backend and shared auth/payment/storage logic.
• web-app/ for TanStack Start landing, /app, and /admin.
• mobile-app/ for Expo Router, React Native, NativeWind, store payments, and mobile UX. </objective>

<first_steps>

1. Identify the affected surface: Convex, web, mobile, or cross-surface.
2. Read the matching rule file before editing:
   • .agents/rules/convex.md
   • .agents/rules/web-app.md
   • .agents/rules/mobile-app.md
   • .agents/rules/auth-payments-storage.md
   • .agents/rules/development-commands.md
3. Before touching convex/, read convex/_generated/ai/guidelines.md.
4. Gather the cheapest real signal available: build/typecheck output, route behavior, screen flow, query callsites, logs, or measured slow path. </first_steps>

<decision_tree>

Problem	Preferred path
Convex reads are expensive, .filter() scans, missing indexes, high docs read	Use convex-cost-optimizer or convex-performance-audit first
Convex schema/data shape needs a rollout	Use convex-migration-helper
Web route state, admin rendering, landing bundle, TanStack Router behavior	Work in web-app/ and verify with web typecheck/build
Mobile render jank, onboarding/paywall flow, NativeWind layout, auth store state	Work in mobile-app/ and verify with TypeScript/lint plus simulator when needed
Shared auth, payments, R2, account behavior	Treat Convex + web + mobile as one contract and verify every touched surface
</decision_tree>

<patterns> ## Convex

• Use indexes for bounded reads; avoid broad .filter() on hot paths.
• Keep authorization in Convex helpers and return DTOs suitable for clients.
• Avoid duplicating backend state into local frontend stores when Convex subscriptions can be the source of truth.
• Prefer targeted pagination and summary records only when there is measured or clearly unbounded read cost.

Web App

• Keep route files under web-app/app/routes/.
• Use @/*, @convex/*, and @site-config aliases already configured in web-app.
• Keep /admin dense and operational; do not optimize by replacing useful tables with marketing-style cards.
• Use existing Base UI/shadcn primitives in web-app/app/components/ui/ before adding new primitives.

Mobile App

• Keep screen state local unless it must survive navigation or be shared across screens.
• Use the existing mobile auth/store helpers before adding a new state library.
• Prefer stable dimensions for buttons, footers, headers, and onboarding/paywall surfaces to avoid layout shifts.
• Avoid network-dependent screenshot/store flows; use deterministic demo paths when preparing release assets.

Cross-Surface

• site-config.ts is the shared source for product, URLs, bundle id, payment ids, and auth origins.
• iOS production payments use Apple IAP. Do not replace that with Stripe checkout.
• Android and web may use Stripe, with server-side payment logic in Convex.
• R2 credentials and backend runtime secrets belong in Convex env, not committed app env files. </patterns>

<verification> Pick the narrowest set that covers the touched surface:

npx convex dev --once
cd web-app && npm run typecheck
cd web-app && npm run build
cd mobile-app && npx tsc --noEmit
cd mobile-app && npm run lint

For visible web behavior, run cd web-app && npm run dev and verify the relevant route. For mobile behavior, use Expo/simulator verification when the change affects navigation, native APIs, payments, screenshots, or layout. </verification>

<anti_patterns>

• Do not introduce Prisma, PostgreSQL, Supabase, Firebase, Redis, or DB mirroring.
• Do not assume org-scoped SaaS routes such as /orgs/$orgSlug; this repo's current product model is mobile-first.
• Do not copy web-only Zustand, TanStack Form, or TanStack Query patterns unless the dependency and local convention already exist.
• Do not optimize from taste alone. Tie larger refactors to a real signal or an obviously unbounded path. </anti_patterns>