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/hooks/useReadingPlans.js

@@ -4,9 +4,9 @@
 // Saved locally right away; synced to the server via an effect that watches
 // `state` (see below) so sync success/failure can actually be tracked and
 // shown, instead of being a fire-and-forget call buried inside setState.
-import { useCallback, useEffect, useRef, useState } from 'react';
+import { useCallback, useEffect, useMemo, useRef, useState } from 'react';
 import { getRemoteReadingProgress, saveRemoteReadingProgress } from '../syncService.js';
-import { localDateString, registerCustomPlans } from '../utils/readingPlans.js';
+import { clampPlanDays, localDateString, normalizeCustomPlan, registerCustomPlans } from '../utils/readingPlans.js';
 
 const STORAGE_KEY = 'readingPlanProgress';
 
@@ -46,6 +46,8 @@ export function useReadingPlans() {
   // Keeps the readingPlans.js lookup (getPlan/getPlanSchedule) in sync with
   // this user's custom plans before any consumer renders this commit.
   registerCustomPlans(state.customPlans);
+  // What the rest of the app sees: plans with more days than chapters are clamped.
+  const customPlans = useMemo(() => state.customPlans.map(normalizeCustomPlan), [state.customPlans]);
 
   // Persist locally + sync to the server whenever state changes. Runs as a
   // real effect (not inside the setState updater) so the network call has a
@@ -198,7 +200,7 @@ export function useReadingPlans() {
         category: 'My Plans',
         icon: '✨',
         image: image || undefined,
-        days: Math.max(1, Math.round(days)),
+        days: clampPlanDays(books, chapterRanges, days),
         books,
         chapterRanges: chapterRanges && Object.keys(chapterRanges).length > 0 ? chapterRanges : undefined,
         custom: true,
@@ -279,7 +281,7 @@ export function useReadingPlans() {
 
   return {
     planProgress: state.progress,
-    customPlans: state.customPlans,
+    customPlans,
     readingActivity: state.activity,
     readingPlanSyncStatus: syncStatus,
     readingPlanSyncError: syncError,