Add Outline stage, parallel reading, offline saves, backup, sync-conflict handling and more

Study
- New Outline stage (hierarchical I./A./1. points, linked to chunks, in all exports);
  the chunk stage is now "Chunks"
- Home cards: passages shown as ranges, tags capped with "+N more"

Reader
- Side-by-side translations and a Compare tab per verse
- Typeface, line spacing, verse-number settings; text and column scale with the screen
- Highlights/bookmarks sheet with named colours (synced); BSB footnote spacing fix
- Cmd-K palette (passages, studies, notes, marks), keyboard shortcuts and "?" help

Flow and safety
- Toasts with Undo replace most confirm()/alert()
- Back/Forward move between pages
- Server refuses saves over a newer copy (409); keep-mine / use-other banner;
  opening a study no longer re-stamps it
- Latest chapter request wins when flipping quickly

Offline and data
- Save books, plan days or a whole BSB/NET for offline
- Service worker fixes: helloao /api/ URLs were skipped and responses cloned too late
- Settings: download/restore a full backup

Accessibility
- Sheets trap focus and close on Escape, skip link, focus ring, reduced motion,
  theme contrast raised to 4.5:1 (with a test)

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

src/pages/ScriptPage.jsx

@@ -3,6 +3,7 @@
 // pronunciation guide live here because this is where they're needed.
 import { useState } from 'react';
 import { useApp } from '../context/AppContext.js';
+import { useToast } from '../components/Toasts.jsx';
 import StudioShell from '../components/study/StudioShell.jsx';
 import { formatChunkReference } from '../utils/bibleUtils.jsx';
 import { buildClaudePrompt, buildPodcastPrompt } from '../utils/exportBuilders.js';
@@ -15,6 +16,7 @@ const btn = 'rounded-lg border border-[var(--r-line)] px-3 py-1.5 text-xs hover:
 export default function ScriptPage() {
   const { project, allChunks, updateProject, updateChunk, authUser, setSaveStatus, setCurrentPage } = useApp();
   const [notice, setNotice] = useState('');
+  const { toast } = useToast();
 
   const chunk = allChunks.find((c) => c.id === project?.selectedChunkId) ?? allChunks[0] ?? null;
   const chapterIndex = chunk ? project.chapters.findIndex((ch) => ch.chunks.some((c) => c.id === chunk.id)) : -1;
@@ -26,9 +28,11 @@ export default function ScriptPage() {
   const set = (patch) => updateChunk(chunk.id, patch);
   const append = (text) => set({ finalScript: script.trim() ? `${script.replace(/\s+$/, '')}\n\n${text}` : text });
 
+  // Replaces the script with an outline from your notes — and says how to get the old one back.
   const draft = () => {
-    if (has(script) && !window.confirm('Replace the current script with a fresh outline from your notes?')) return;
+    const before = script;
     set({ finalScript: buildScriptDraft(chunk, reference) });
+    if (has(before)) toast('Script replaced with a fresh outline', { action: { label: 'Undo', onClick: () => set({ finalScript: before }) } });
   };
 
   const importDocx = async (file) => {