feat: show page numbers on page-break markers in Script Rehearser

When a PDF audiobook is cast and saved to the Rehearser, page breaks now
carry the source PDF page number. In the Stage view each divider renders
as "— Page N —" instead of the generic "— Page break —".

Implementation:
- audiobook.js: `audiobookBuildScript()` encodes the page number in the
  form-feed line (\fN instead of bare \f) at each page boundary.
- rehearser-parse.js: `parseScript()` now matches `line.startsWith('\f')`
  and extracts the trailing page number into `line.page`.
- rehearser.js: `buildScriptPage()` renders "— Page N —" when `line.page`
  is set; `toScript()` round-trips the number back (\fN) so it survives
  save/reload; `importPDFScript()` also encodes page numbers (\f<pageIdx+1>)
  when importing screenplay PDFs directly.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

CHANGELOG.md

@@ -9,6 +9,13 @@ Follows [Keep a Changelog](https://keepachangelog.com/en/1.0.0/) · versioned wi
 
 ---
 
+## [1.9.4] — 2026-06-26
+
+### Changed
+- **Audiobook casting — page numbers in Rehearser**: page-break markers now carry the source PDF page number. In the Script Rehearser Stage, each page divider shows **"— Page N —"** instead of the generic "— Page break —", making it easy to cross-reference the audiobook script against the book. Applies both to audiobooks cast from Read Aloud PDFs and to screenplay PDFs imported directly into the Rehearser.
+
+---
+
 ## [1.9.3] — 2026-06-26
 
 ### Added

VERSION

@@ -1 +1 @@
-1.9.3
+1.9.4

static/index.html

@@ -26,7 +26,7 @@
 
   <!-- ── Core styles (local — no CDN dependency for first paint) ────────── -->
   <link rel="stylesheet" href="/static/vendor/mdi/materialdesignicons.min.css">
-  <link rel="stylesheet" href="/static/style.css?v=1.9.3">
+  <link rel="stylesheet" href="/static/style.css?v=1.9.4">
 
 
   <!-- ── Flag icons — non-blocking (loaded async, icons appear after JS) ── -->
@@ -308,7 +308,7 @@
 <script src="/static/vendor/wavesurfer-regions.min.js"></script>
 
 <!-- loader.js: fetches sections → loads JS modules → removes skeleton -->
-<script src="/static/loader.js?v=1.9.3"></script>
+<script src="/static/loader.js?v=1.9.4"></script>
 
 </body>
 </html>

static/js/audiobook.js

@@ -1291,7 +1291,10 @@ function audiobookBuildScript(segments) {
       const pos = at >= 0 ? at : searchPos;
       if (at >= 0) searchPos = at + probe.length;
       while (markIdx < marks.length && pos >= marks[markIdx].offset) {
-        if (script.trim()) script += '\n\f\n';   // page break before this segment
+        if (script.trim()) {
+          const pn = marks[markIdx].page;
+          script += pn ? `\n\f${pn}\n` : '\n\f\n';  // page break with page number
+        }
         markIdx++;
       }
     }

static/js/rehearser-parse.js

@@ -54,10 +54,13 @@ function parseScript(text) {
       continue;
     }
 
-    // PDF page-break marker — preserved from importPDFScript
+    // PDF page-break marker — preserved from importPDFScript / audiobook casting
-    if (line === '\f') {
+    // Format: bare \f or \f<number> (e.g. \f3 = page 3)
+    if (line.startsWith('\f')) {
       flushDialog(); flushAction();
-      result.push({ type: 'pagebreak', speaker: '', text: '', isDirection: true });
+      const pnStr = line.slice(1).trim();
+      const pageNum = pnStr && /^\d+$/.test(pnStr) ? parseInt(pnStr, 10) : null;
+      result.push({ type: 'pagebreak', speaker: '', text: '', page: pageNum, isDirection: true });
       state = 'action'; currentSpeaker = null;
       continue;
     }

static/js/rehearser.js

@@ -204,7 +204,7 @@ function linesToScriptText() {
       case 'dialog':      return '\n' + line.speaker + '\n' + line.text + '\n';
       case 'direction':
         return line.speaker ? line.text + '\n' : '\n' + line.text + '\n';
-      case 'pagebreak':   return '\n\f\n';
+      case 'pagebreak':   return line.page ? `\n\f${line.page}\n` : '\n\f\n';
       default:            return '';
     }
   }).join('').trim();
@@ -450,7 +450,7 @@ async function importPDFScript(file) {
 
   for (let pageIdx = 0; pageIdx < pdf.numPages; pageIdx++) {
     // Emit a page-break marker between PDF pages so the rehearser can paginate exactly
-    if (pageIdx > 0) { blank(); out.push('\f'); blank(); }
+    if (pageIdx > 0) { blank(); out.push(`\f${pageIdx + 1}`); blank(); }
 
     const pageLns = allLinesByPage[pageIdx] || [];
     for (const ln of pageLns) {
@@ -2239,8 +2239,10 @@ function buildScriptPage() {
           ${editBtn} ${synthDot}
         </div>`;
 
-      case 'pagebreak':
+      case 'pagebreak': {
-        return `<div class="reh-block-pagebreak${lineFlags}" data-index="${i}">${bulkCheck}<span class="reh-pagebreak-label">— Page break —</span></div>`;
+        const pbLabel = line.page ? `— Page ${line.page} —` : '— Page break —';
+        return `<div class="reh-block-pagebreak${lineFlags}" data-index="${i}">${bulkCheck}<span class="reh-pagebreak-label">${pbLabel}</span></div>`;
+      }
 
       case 'transition':
         return `<div class="reh-transition${lineFlags}" data-index="${i}">${bulkCheck}${escHtml(line.text)}</div>`;