fix(audio): stop the Script Director from splitting off punctuation-only cards

Sentence splitting cut after every '…', so "嗯……" produced a card holding only
"…"; stacked marks ("？！") and closing quotes ("！」") were split off the same way.

- split only at 。！？!? and a lone '.' before whitespace; ellipses never split
- stacked end marks and trailing quotes/brackets stay with their sentence
- punctuation-only pieces (either split mode) are attached to a neighbour
- new ✂ button splits a card at the text cursor, complementing merge

Verified: tests/audio_script_rules.mjs (ellipsis, quotes, stacked marks,
punctuation-only lines, caret split) and a jsdom walkthrough of split/merge.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01W411Z69FC3em9CzpeqEub5

web/modules/audio_script.js

@@ -19,16 +19,63 @@ export function comboValueForPath(widget, relativePath) {
     return values.find(value => normalisePath(value) === wanted) ?? null;
 }
 
+const SENTENCE_END = new Set(['。', '！', '？', '!', '?']);
+// Closing quotes/brackets and trailing marks that belong to the sentence they follow.
+const TRAILING = new Set(['。', '！', '？', '!', '?', '」', '』', '”', '’', '"', "'", '）', ')', '】', '》', '〉', '~', '～']);
+const SPEAKABLE = /[\p{L}\p{N}]/u;
+
+function splitSentences(line) {
+    const chars = [...line];
+    const segments = [];
+    let current = '';
+    for (let i = 0; i < chars.length; i++) {
+        const char = chars[i];
+        current += char;
+        // A single '.' ends an English sentence only before whitespace; '3.5', '...' and '……' do not split.
+        const isPeriod = char === '.' && chars[i - 1] !== '.' && chars[i + 1] !== '.' && (i + 1 >= chars.length || /\s/.test(chars[i + 1]));
+        if (!SENTENCE_END.has(char) && !isPeriod) continue;
+        while (i + 1 < chars.length && TRAILING.has(chars[i + 1])) current += chars[++i];
+        segments.push(current);
+        current = '';
+    }
+    segments.push(current);
+    return segments;
+}
+
+/** Punctuation-only pieces ("……", "！」") cannot be spoken on their own: attach them to a neighbour. */
+function attachUnspeakable(segments) {
+    const result = [];
+    let pending = '';
+    for (const segment of segments) {
+        if (SPEAKABLE.test(segment)) {
+            result.push(pending + segment);
+            pending = '';
+        } else if (result.length) {
+            result[result.length - 1] += segment;
+        } else {
+            pending += segment;
+        }
+    }
+    if (pending) result.push(pending);
+    return result;
+}
+
 /**
- * Split a script into segments. `sentence`: sentence punctuation and newlines
- * ('.' only before whitespace, so 3.5 stays whole). `line`: one segment per line.
+ * Split a script into segments. `sentence`: at 。！？!? (with trailing quotes or
+ * brackets) and newlines; ellipses never split. `line`: one segment per line.
  */
 export function splitScriptLines(text, mode = 'sentence') {
-    const pattern = mode === 'line' ? /\n+/ : /\n+|(?<=[。！？!?…])|(?<=\.)(?=\s)/;
-    return String(text || '')
-        .split(pattern)
-        .map(line => line.trim())
-        .filter(Boolean);
+    const lines = String(text || '').split(/\n+/).map(line => line.trim()).filter(Boolean);
+    const segments = mode === 'line' ? lines : lines.flatMap(splitSentences);
+    return attachUnspeakable(segments.map(segment => segment.trim()).filter(Boolean));
+}
+
+/** Split one segment at a caret position; null when either side would be empty. */
+export function splitSegmentAt(text, position) {
+    const value = String(text || '');
+    const before = value.slice(0, position).trim();
+    const after = value.slice(position).trim();
+    return before && after ? [before, after] : null;
 }
 
 /** Join two segments: a space only between Latin words/digits, none for CJK text. */

web/modules/locales.js

@@ -1344,6 +1344,8 @@ export const i18n = {
         scriptDirectorSplitLine: "按换行分段（每行一张卡片）",
         scriptDirectorMergeNext: "与下一段合并（保留这张卡片的情绪）",
         scriptDirectorAddLine: "+ 添加一段",
+        scriptDirectorSplitAtCaret: "在光标处拆成两段",
+        scriptDirectorSplitHint: "先在这段文字里点一下要断开的位置，再点 ✂",
         scriptDirectorEmpty: "还没有台词，请先粘贴剧本并解析分句",
         audioTagUnusable: "这个音色暂时不能用于多音色标签：需要同目录下的主音色（角色.wav）和各自的 .txt 台词，且格式与主音色一致",
         audioMainMissing: "缺少主音色 {file}。F5-TTS 的情绪变体必须和主音色放在一起才能用 {标签} 调用。",
@@ -2697,6 +2699,8 @@ export const i18n = {
         scriptDirectorSplitLine: "Split by line (one card per line)",
         scriptDirectorMergeNext: "Merge with the next segment (keeps this card's emotion)",
         scriptDirectorAddLine: "+ Add segment",
+        scriptDirectorSplitAtCaret: "Split into two at the cursor",
+        scriptDirectorSplitHint: "Click where the text should break, then press ✂",
         scriptDirectorEmpty: "No lines yet. Paste a script and parse it first.",
         audioTagUnusable: "This voice cannot be used as a multi-voice tag yet: it needs the main voice (Character.wav) in the same folder, .txt transcripts for both, and the same format as the main voice",
         audioMainMissing: "Main voice {file} is missing. F5-TTS only finds emotion variants next to their main voice.",

web/modules/ui_script_director.js

@@ -1,7 +1,7 @@
 import { app } from '../../../scripts/app.js';
 import { t } from './interface_settings.js';
 import { anomalousAlert, anomalousConfirm } from './ui_dialog.js';
-import { buildScriptPackage, comboValueForPath, joinSegments, splitScriptLines, usableEmotions } from './audio_script.js';
+import { buildScriptPackage, comboValueForPath, joinSegments, splitScriptLines, splitSegmentAt, usableEmotions } from './audio_script.js';
 import { bindMaterialDrag } from './material_drag.js';
 
 /**
@@ -250,6 +250,20 @@ function renderLineCard(line, index, emotions, slices) {
     head.append(
         el('span', 'anomalous-sd-line-no', `#${index + 1}`),
         previewBtn,
+        // Split at the text caret (the textarea keeps its caret after losing focus to this button).
+        button('anomalous-sd-icon-btn', '✂', async () => {
+            const parts = splitSegmentAt(line.text, text.selectionStart);
+            if (!parts) {
+                await anomalousAlert(t('scriptDirectorSplitHint'));
+                text.focus();
+                return;
+            }
+            line.text = parts[0];
+            state.lines.splice(index + 1, 0, { text: parts[1], emotion: line.emotion });
+            state.focusIndex = index + 1;
+            stopScriptDirectorPreview();
+            renderAll();
+        }, t('scriptDirectorSplitAtCaret')),
     );
     if (index < state.lines.length - 1) {
         // Merge keeps this card's emotion: one card = one segment spoken with one voice.