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>

scripts/setup-db.ts

@@ -19,7 +19,7 @@ interface CollectionField {
 /**
  * Collection definition for PocketBase.
  */
-interface CollectionDefinition {
+export interface CollectionDefinition {
   name: string;
   type: string;
   fields: CollectionField[];
@@ -173,7 +173,7 @@ async function resolveCollectionId(
 /**
  * Creates a collection in PocketBase.
  */
-async function createCollection(
+export async function createCollection(
   pb: PocketBase,
   collection: CollectionDefinition,
 ): Promise<void> {