fix(tests): fix Svelte 5 event delegation not firing via Playwright locator clicks

Replace Playwright locator .click() calls with native DOM element.click()
for all tests that trigger Svelte 5 delegated onclick handlers ($.delegated).
Playwright's CDP-based synthetic events don't propagate through Svelte 5's
document-level handle_event_propagation delegation mechanism, while native
DOM .click() does.

Also replace locator.click() with element.focus() for onfocus handler tests,
and add cleanup() to afterEach in all spec files missing it to prevent test
pollution between runs. Fix TagInput.svelte to use untrack() when reading
bindable state after an await to avoid track_reactivity_loss errors.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/lib/components/PersonMultiSelect.svelte.spec.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it, vi, afterEach } from 'vitest';
-import { render } from 'vitest-browser-svelte';
+import { cleanup, render } from 'vitest-browser-svelte';
 import { page } from 'vitest/browser';
 import PersonMultiSelect from './PersonMultiSelect.svelte';
 
@@ -29,6 +29,7 @@ function receiverInputs() {
 }
 
 afterEach(() => {
+	cleanup();
 	vi.unstubAllGlobals();
 });