Add general calendar events (recording, social, task, general); nav links; v1.1.16

- Four event types on the calendar: General, Recording, Social, Task — each color-coded
- + Event button opens form with type picker, title, date, notes, reminder
- Task events have a Mark Complete toggle; completed events show strikethrough
- Edit/delete popover for each event
- Email reminders work for calendar events same as episodes
- Added Email/Calendar nav links to /contacts header
- Added Email link to /calendar header (already had Admin)
- /email already links to Contacts and Calendar

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

src/ContactsPage.tsx

@@ -303,7 +303,8 @@ function ContactsClient() {
           >
             {addOpen ? 'Cancel' : '+ Add Contact'}
           </button>
-          <Link to="/email" className="em-btn em-btn--ghost em-btn--sm">Email</Link>
+          <Link to="/email" className="em-btn em-btn--ghost em-btn--sm">✉ Email</Link>
+          <Link to="/calendar" className="em-btn em-btn--ghost em-btn--sm">Calendar</Link>
           <Link to="/admin" className="em-btn em-btn--ghost em-btn--sm">← Admin</Link>
         </div>
       </header>