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/auth.setup.ts

@@ -0,0 +1,33 @@
+import { test as setup, expect } from '@playwright/test';
+
+const authFile = 'playwright/.auth/user.json';
+
+setup('authenticate', async ({ page }) => {
+  // Create user if not exists (global setup should have done it, but be safe)
+  const resp = await page.request.post('/api/auth/register', {
+    data: {
+      username: 'e2e_testuser',
+      password: 'TestPassword123!',
+      email: 'e2e@example.com',
+      full_name: 'E2E Test User',
+    },
+  });
+  if (!resp.ok() && resp.status() !== 400) {
+    console.warn('Register failed:', await resp.text());
+  }
+
+  // Login via UI
+  await page.goto('/login');
+  await page.fill('#loginUsername', 'e2e_testuser');
+  await page.fill('#loginPassword', 'TestPassword123!');
+
+  await Promise.all([
+    page.waitForResponse((resp) => resp.url().includes('/api/auth/login')),
+    page.click('#loginSubmit'),
+  ]);
+
+  await page.waitForURL('**/web**', { timeout: 10000 });
+
+  // Save storage state (localStorage + cookies)
+  await page.context().storageState({ path: authFile });
+});