Add self-contained e2e test harness with ephemeral PocketBase

Previously, 15 e2e tests were skipped because TEST_USER_EMAIL and
TEST_USER_PASSWORD env vars weren't set. Now the test harness:

- Starts a fresh PocketBase instance in /tmp on port 8091
- Creates admin user, collections, and API rules automatically
- Seeds test user with period data for authenticated tests
- Cleans up temp directory after tests complete

Also fixes:
- Override toggle tests now use checkbox role (not button)
- Adds proper wait for OVERRIDES section before testing toggles
- Suppresses document.cookie lint warning with explanation

Test results: 64 e2e tests pass, 1014 unit tests pass

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

e2e/global-setup.ts

@@ -0,0 +1,32 @@
+// ABOUTME: Playwright global setup - starts PocketBase and sets test environment variables.
+// ABOUTME: Runs before all e2e tests to provide a fresh database with test data.
+import * as fs from "node:fs";
+import * as path from "node:path";
+import { DEFAULT_CONFIG, start } from "./pocketbase-harness";
+
+const STATE_FILE = path.join(__dirname, ".harness-state.json");
+
+export default async function globalSetup(): Promise<void> {
+  console.log("Starting PocketBase for e2e tests...");
+
+  const state = await start(DEFAULT_CONFIG);
+
+  // Save state for teardown
+  fs.writeFileSync(
+    STATE_FILE,
+    JSON.stringify({
+      dataDir: state.dataDir,
+      url: state.url,
+      pid: state.process.pid,
+    }),
+  );
+
+  // Set environment variables for the test process
+  process.env.NEXT_PUBLIC_POCKETBASE_URL = state.url;
+  process.env.POCKETBASE_URL = state.url;
+  process.env.TEST_USER_EMAIL = DEFAULT_CONFIG.testUserEmail;
+  process.env.TEST_USER_PASSWORD = DEFAULT_CONFIG.testUserPassword;
+
+  console.log(`PocketBase running at ${state.url}`);
+  console.log(`Test user: ${DEFAULT_CONFIG.testUserEmail}`);
+}