Add Playwright fixtures with 5 test user types for e2e tests

Creates test infrastructure to enable previously skipped e2e tests:
- Onboarding user (no period data) for setup flow tests
- Established user (period 14 days ago) for normal usage tests
- Calendar user (with calendarToken) for ICS feed tests
- Garmin user (valid tokens) for connected state tests
- Garmin expired user (expired tokens) for expiry warning tests

Also fixes ICS feed route to strip .ics suffix from Next.js dynamic
route param, adds calendarToken to /api/user response, and sets
viewRule on users collection for unauthenticated ICS access.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

e2e/fixtures.ts

@@ -0,0 +1,86 @@
+// ABOUTME: Playwright test fixtures for different user states.
+// ABOUTME: Provides pre-authenticated pages for onboarding, established, calendar, and garmin users.
+import { test as base, type Page } from "@playwright/test";
+import { TEST_USERS, type TestUserPreset } from "./pocketbase-harness";
+
+/**
+ * Logs in a user via the email/password form.
+ * Throws if the email form is not visible (OIDC-only mode).
+ */
+async function loginUser(
+  page: Page,
+  email: string,
+  password: string,
+): Promise<void> {
+  await page.goto("/login");
+  await page.waitForLoadState("networkidle");
+
+  const emailInput = page.getByLabel(/email/i);
+  const hasEmailForm = await emailInput.isVisible().catch(() => false);
+
+  if (!hasEmailForm) {
+    throw new Error(
+      "Email/password form not visible - app may be in OIDC-only mode",
+    );
+  }
+
+  await emailInput.fill(email);
+  await page.getByLabel(/password/i).fill(password);
+  await page.getByRole("button", { name: /sign in/i }).click();
+
+  // Wait for successful redirect to dashboard
+  await page.waitForURL("/", { timeout: 15000 });
+}
+
+/**
+ * Creates a fixture for a specific user preset.
+ */
+function createUserFixture(preset: TestUserPreset) {
+  return async (
+    { page }: { page: Page },
+    use: (page: Page) => Promise<void>,
+  ) => {
+    const user = TEST_USERS[preset];
+    await loginUser(page, user.email, user.password);
+    await use(page);
+  };
+}
+
+/**
+ * Extended test fixtures providing pre-authenticated pages for each user type.
+ *
+ * Usage:
+ *   import { test, expect } from './fixtures';
+ *
+ *   test('onboarding user sees set date button', async ({ onboardingPage }) => {
+ *     await onboardingPage.goto('/');
+ *     // User has no period data, will see onboarding UI
+ *   });
+ *
+ *   test('established user sees dashboard', async ({ establishedPage }) => {
+ *     await establishedPage.goto('/');
+ *     // User has period data from 14 days ago
+ *   });
+ */
+type TestFixtures = {
+  /** User with no period data - sees onboarding UI */
+  onboardingPage: Page;
+  /** User with period data (14 days ago) - sees normal dashboard */
+  establishedPage: Page;
+  /** User with period data and calendar token - can copy/regenerate URL */
+  calendarPage: Page;
+  /** User with valid Garmin tokens (90 days until expiry) */
+  garminPage: Page;
+  /** User with expired Garmin tokens */
+  garminExpiredPage: Page;
+};
+
+export const test = base.extend<TestFixtures>({
+  onboardingPage: createUserFixture("onboarding"),
+  establishedPage: createUserFixture("established"),
+  calendarPage: createUserFixture("calendar"),
+  garminPage: createUserFixture("garmin"),
+  garminExpiredPage: createUserFixture("garminExpired"),
+});
+
+export { expect } from "@playwright/test";