feat(engagement): localize limits and streaks

Use reported user timezones for daily response limits, expose couple streak state and reminders, and improve swipe and live-drawing synchronization with focused tests and documentation.

apps/mobile/src/__tests__/features/swipe/useSwipeScreen-helpers.test.ts

@@ -0,0 +1,40 @@
+import { calculateEffectiveTotal } from "@/features/swipe/utils/useSwipeScreen-helpers";
+import type { DailyLimitInfo } from "@/features/swipe/types";
+
+const limit = (overrides: Partial<DailyLimitInfo> = {}): DailyLimitInfo => ({
+    responses_today: 0,
+    limit_value: 10,
+    remaining: 10,
+    reset_at: "2026-08-29T00:00:00.000Z",
+    is_blocked: false,
+    ...overrides,
+});
+
+describe("calculateEffectiveTotal", () => {
+    it("clamps the progress bar to the quota left today", () => {
+        expect(calculateEffectiveTotal(50, null, limit({ responses_today: 8, remaining: 2 }), 3)).toBe(5);
+    });
+
+    it("shows the last card as the last card when one answer remains", () => {
+        expect(calculateEffectiveTotal(50, null, limit({ responses_today: 9, remaining: 1 }), 7)).toBe(8);
+    });
+
+    it("leaves the total alone when the meter is disabled", () => {
+        expect(calculateEffectiveTotal(50, null, limit({ limit_value: 0, remaining: 0 }), 3)).toBe(50);
+        expect(calculateEffectiveTotal(50, null, null, 3)).toBe(50);
+    });
+
+    it("ignores the quota once blocked, since the limit screen takes over", () => {
+        expect(calculateEffectiveTotal(50, null, limit({ responses_today: 10, remaining: 0, is_blocked: true }), 3)).toBe(50);
+    });
+
+    it("takes whichever of the answer gap and the quota binds first", () => {
+        const gap = { unanswered: 8, threshold: 10 };
+        expect(calculateEffectiveTotal(50, gap, limit({ remaining: 5 }), 2)).toBe(4);
+        expect(calculateEffectiveTotal(50, gap, limit({ remaining: 1 }), 2)).toBe(3);
+    });
+
+    it("never runs fewer questions than the quota allows", () => {
+        expect(calculateEffectiveTotal(3, null, limit({ remaining: 10 }), 0)).toBe(3);
+    });
+});