test: real backend pytest + E2E Playwright suites, both isolated from prod data

backend/tests/: 33 pytest tests against a real Postgres database
(aurum_test, created/migrated/dropped per run) exercised through the actual
HTTP API — not sqlite, not mocks, and the real `aurum` database is never
opened (app lifespan is skipped, get_session is overridden per test).
Covers transaction category-kind validation, year/month/date-range
filtering and pagination, dashboard summary arithmetic, budget status, cash
flow, and the /transactions/years picker.

e2e/: 6 Playwright specs driving a real browser against a fully separate
throwaway docker-compose stack (run.sh: separate project name, database,
port, and volume, torn down with `down -v` on exit) — regression coverage
for the Recent Transactions month bug, the Card grid-overflow bug, the
frozen-year bug, the Net Worth default range, and the Dashboard->
Transactions deep link, all fixed earlier this session.

Also synced the backend's APP_VERSION constant (stale at 0.15.2, embedded
in exported backups) with the frontend version.

e2e/tests/net-worth-default-range.spec.ts

@@ -0,0 +1,19 @@
+import { test, expect } from "@playwright/test";
+
+// Regression for v0.17.1: Net Worth defaulted to a 30-day window, which
+// frequently shows a dip just from short-window noise even when the
+// long-run trend is a climb — demotivating for no good reason. Should
+// default to 5 years instead. See UPDATES.md (v0.17.1) and
+// frontend/src/pages/NetWorthPage.tsx.
+test("Net Worth opens with the 5Y range active, not 30D", async ({ page }) => {
+  await page.goto("/net-worth");
+
+  const fiveYearButton = page.getByRole("button", { name: "5Y", exact: true });
+  const thirtyDayButton = page.getByRole("button", { name: "30D", exact: true });
+  await expect(fiveYearButton).toBeVisible();
+
+  const fiveYearClass = await fiveYearButton.getAttribute("class");
+  const thirtyDayClass = await thirtyDayButton.getAttribute("class");
+  expect(fiveYearClass).toContain("bg-surface-2");
+  expect(thirtyDayClass).not.toContain("bg-surface-2");
+});