Unify entities navigation, redesign time clock, and add invoice PDF preview.

Combine clients and businesses under entities, polish the web time clock,
and show live invoice PDF preview with tighter line-item editing.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/lib/time-clock-prefs.ts

@@ -0,0 +1,11 @@
+const STORAGE_KEY = "beenvoice:time-clock:last-client";
+
+export function getLastTimeClockClientId(): string | null {
+  if (typeof window === "undefined") return null;
+  return localStorage.getItem(STORAGE_KEY);
+}
+
+export function setLastTimeClockClientId(clientId: string): void {
+  if (!clientId || typeof window === "undefined") return;
+  localStorage.setItem(STORAGE_KEY, clientId);
+}