fix: migrations, auth, providers health check, E2E tests, remove neko-sama

- Add proper Alembic initial migration (0001_initial_schema.py)
- Migrate refresh tokens from JSON file to SQLite (RefreshTokenTable)
- Remove Neko-Sama provider entirely (redirects to Gupy, not a host)
- Fix provider health check always showing UNKNOWN
  - Run check_all_health() on startup
  - Fix POST /providers/health/check background task bug
  - Add HTMX refresh after manual health check trigger
- Fix anime search relevance scoring with MIN_RELEVANCE_THRESHOLD=0.5
- Replace bare 'except:' with 'except Exception:' across codebase
- Add Playwright E2E test suite (12 tests, auth setup, helpers)
- Fix toast container blocking clicks via pointer-events: none
- Remove obsolete Jest/Vite test files and config
- Clean up obsolete test_watchlist scripts
- Update sonarr model comment for active providers

tests/e2e/global-setup.ts

@@ -0,0 +1,29 @@
+/**
+ * Global setup for E2E tests.
+ * Creates a predictable test user so auth tests don't fail on missing accounts.
+ * Uses native fetch to avoid conflicts with vitest.
+ */
+export default async function globalSetup() {
+  const baseURL = process.env.PLAYWRIGHT_BASE_URL || 'http://localhost:3000';
+
+  const testUser = {
+    username: 'e2e_testuser',
+    password: 'TestPassword123!',
+    email: 'e2e@example.com',
+    full_name: 'E2E Test User',
+  };
+
+  // Try to register the test user (ignore 400 if already exists)
+  const resp = await fetch(`${baseURL}/api/auth/register`, {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify(testUser),
+  });
+
+  if (resp.ok || resp.status === 400) {
+    console.log(`[global-setup] Test user "${testUser.username}" ready`);
+  } else {
+    const body = await resp.text().catch(() => '');
+    console.warn(`[global-setup] Register returned ${resp.status}: ${body}`);
+  }
+}