Fix plan days with no chapters, add a way out of ink mode, harden ntfy reminders

Plans can no longer have more days than chapters (existing ones heal), and
opening a plan never strands the Reader on an empty day. The Reader shows
Done drawing while inking (Escape also exits). Reminders use the user's own
timezone, send within a 3 hour grace window, and Settings has a Send test
notification button.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/App.test.jsx

@@ -950,3 +950,19 @@ describe('Study layout', () => {
     expect(within(screen.getByRole('region', { name: 'Scripture' })).queryByRole('textbox')).not.toBeInTheDocument();
   });
 });
+
+describe('Reading plan with more days than chapters', () => {
+  test('Continue reading opens the plan on a real chapter instead of stranding the Reader', async () => {
+    localStorage.setItem('readingPlanProgress', JSON.stringify({
+      customPlans: [{ id: 'custom-luke', title: 'Luke', days: 90, books: ['LUK'], custom: true }],
+      progress: [{ id: 'rp1', planId: 'custom-luke', startedAt: Date.now(), completedDays: [0, 1], chaptersRead: {}, completedAt: null, lastActivityAt: Date.now() }],
+      activity: [],
+    }));
+    const user = userEvent.setup();
+    await renderApp();
+    await user.click(await screen.findByRole('button', { name: /continue reading/i }));
+    expect(await screen.findByText(/Luke 3 · BSB/)).toBeInTheDocument();
+    expect(screen.getAllByText(/Luke · Day 3/).length).toBeGreaterThan(0);
+    expect(screen.queryByText(/back to today.s reading/i)).not.toBeInTheDocument();
+  });
+});