test: add unit tests for rate limiter middleware

docs/superpowers/specs/2026-04-03-code-quality-round2-design.md

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+# Code Quality Improvements (Round 2) Design
+
+**Date:** 2026-04-03
+**Scope:** Combined formatters hook, test helper schema generation, stale todo cleanup
+
+## 1. useFormatters Combined Hook
+
+**Problem:** 14 component files import the same 3-4 lines: `useWeightUnit`, `useCurrency`, `formatWeight`, `formatPrice`. This is repetitive boilerplate.
+
+**Solution:** Create `src/client/hooks/useFormatters.ts` that returns pre-bound formatting functions:
+
+```ts
+export function useFormatters() {
+  const unit = useWeightUnit();
+  const currency = useCurrency();
+  return {
+    weight: (grams: number | null) => formatWeight(grams, unit),
+    price: (cents: number | null) => formatPrice(cents, currency),
+    unit,
+    currency,
+  };
+}
+```
+
+**Consumer files to update (14):**
+- CollectionView.tsx
+- setups/$setupId.tsx
+- routes/index.tsx
+- WeightSummaryCard.tsx
+- TotalsBar.tsx
+- settings.tsx
+- ThreadCard.tsx
+- SetupCard.tsx
+- ItemPicker.tsx
+- ItemCard.tsx
+- ComparisonTable.tsx
+- CandidateCard.tsx
+- CandidateListItem.tsx
+- CategoryHeader.tsx
+
+Each file replaces 3-4 imports + 2 hook calls with 1 import + 1 destructured hook call. Components that need raw `unit` or `currency` (e.g., WeightSummaryCard uses `unit` as a type, TotalsBar has a unit toggle) get them from the return object.
+
+## 2. Test Helper Schema Generation
+
+**Problem:** `tests/helpers/db.ts` has 120 lines of hand-written CREATE TABLE SQL that must manually mirror `src/db/schema.ts`. Any schema change requires updating both files — a known source of `SqliteError: no such column` failures.
+
+**Solution:** Replace hand-written SQL with Drizzle's migration runner:
+
+```ts
+import { migrate } from "drizzle-orm/bun-sqlite/migrator";
+
+export function createTestDb() {
+  const sqlite = new Database(":memory:");
+  sqlite.run("PRAGMA foreign_keys = ON");
+  const db = drizzle(sqlite, { schema });
+  migrate(db, { migrationsFolder: "./drizzle" });
+  db.insert(schema.categories).values({ name: "Uncategorized", icon: "package" }).run();
+  return db;
+}
+```
+
+This reduces the file from ~128 lines to ~15 lines and eliminates all future manual sync.
+
+## 3. Stale Todo Cleanup
+
+**Problem:** Pending todo "Replace planning category filter select with icon-aware dropdown" from 2026-03-15 is already resolved — `PlanningView.tsx` uses `<CategoryFilterDropdown>` which renders Lucide icons.
+
+**Solution:** Move the todo file from `pending/` to `done/`.
+
+## Commit Strategy
+
+1. **useFormatters hook** — create hook + update all 14 consumer files
+2. **Test helper migration** — replace hand-written SQL with migrate()
+3. **Todo cleanup** — move stale todo to done