fix(web): drop indexer debug log, harden settings dialog, escape search-placeholder quotes

Three small cleanups bundled:

- Remove the `console.debug('[indexer]', ...)` line in the indexer
  store. The PhotoPrism WS protocol is now verified; the log was a
  development aid that no longer earns its console noise.

- GeneralSettingsDialog: normalize cloned PpSettings so `ui` / `search`
  / `maps` are always real objects (some deployments return them
  unset), and re-clone the draft on each open instead of nulling it on
  close. The previous lifecycle let Dialog's exit animation keep the
  form mounted while `draft` was already null, which threw at runtime
  via the `bind:value={draft.ui!.theme}` getters.

- Search-input placeholder string: rewrite as a JS expression so the
  embedded `"vacation"` quotes inside the example don't terminate the
  HTML attribute early. The previous form was a Svelte parse error
  that stopped the dev-server module from loading.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

web/src/lib/stores/indexer.svelte.ts

@@ -126,11 +126,6 @@ function handleMessage(raw: string): void {
 	const eventName = inner.event as string | undefined;
 	const data = (inner.data ?? {}) as Record<string, unknown>;
 	if (!eventName) return;
-	// PhotoPrism's WS protocol isn't a stable contract; log the live shape
-	// at `debug` (hidden by default in DevTools — toggle "Verbose" to see)
-	// so future-us can spot new indexer event names without instrumenting
-	// the entire app.
-	console.debug('[indexer]', eventName, data);
 	switch (eventName) {
 		case 'index.indexing': {
 			// Per-file event during the scan pass. PhotoPrism emits one