fix(subtitles): recover positioned ASS word spacing and drop control debris (#217)

src/core/services/ass-text.test.ts

@@ -10,6 +10,8 @@ import {
   isAssTemporalCommand,
   normalizePlainSubtitleText,
   parseAssEffectField,
+  removeLiveGlyphFragmentLines,
+  removeAssControlDebrisLines,
 } from './ass-text';
 
 test('assToPlainText drops vector drawing runs', () => {
@@ -74,6 +76,14 @@ test('assToPlainText normalizes CRLF before converting', () => {
   assert.equal(assToPlainText('一行目\r\n二行目'), '一行目\n二行目');
 });
 
+test('removeAssControlDebrisLines drops malformed spacer resets without eating dialogue', () => {
+  assert.equal(
+    removeAssControlDebrisLines('Visible line\n\\\n{\\fr0\n\\{\\frz287.5'),
+    'Visible line',
+  );
+  assert.equal(removeAssControlDebrisLines('本文{\\pos(1,2)'), '本文{\\pos(1,2)');
+});
+
 test('normalizePlainSubtitleText settles whitespace without decoding ASS', () => {
   // A brace reaching this layer is literal text mpv chose to show, not markup.
   assert.equal(normalizePlainSubtitleText('本文{\\pos(1,2)'), '本文{\\pos(1,2)');
@@ -193,3 +203,18 @@ test('isAnimatedAssEffectKind covers the stock animated effects only', () => {
   assert.equal(isAnimatedAssEffectKind('other'), false);
   assert.equal(isAnimatedAssEffectKind('none'), false);
 });
+
+test('removeLiveGlyphFragmentLines drops a per-glyph typesetting wall and its syllable', () => {
+  const wall = [...'wansdumretoikhI'].join('\n');
+  assert.equal(removeLiveGlyphFragmentLines(`${wall}\ntai`), '');
+});
+
+test('removeLiveGlyphFragmentLines keeps concurrent dialogue beside a glyph wall', () => {
+  const wall = [...'wansdumretoikhI'].join('\n');
+  assert.equal(removeLiveGlyphFragmentLines(`${wall}\nそれよりも　ノート…`), 'それよりも　ノート…');
+});
+
+test('removeLiveGlyphFragmentLines leaves ordinary short lines alone', () => {
+  const text = 'え\nはい。\nそうだな';
+  assert.equal(removeLiveGlyphFragmentLines(text), text);
+});