feat(subtitles): add regex subtitle filters with built-in presets (#318)

- Add `subtitleFilter` config with four presets: parentheses, brackets, speaker prefix and music symbols. Custom regex rules run after the presets.
- Filter primary text where it enters the app (live `sub-text` and parsed cues), so the overlay, sidebar, mining and stats all get the same filtered text.
- Changes hot-reload: the current line is read again and the active track is parsed again, using the filter config as the prefetch parse key.
- Add a custom rule editor in Settings under Behavior → Subtitle Filters that checks patterns as you type.
- Update the config example, the configuration docs and the architecture domains doc, and add a changelog fragment.

src/config/definitions/template-sections.ts

@@ -153,6 +153,15 @@ const SUBTITLE_TEMPLATE_SECTIONS: ConfigTemplateSection[] = [
     notes: ['Hot-reload: subtitle sidebar changes apply live without restarting SubMiner.'],
     key: 'subtitleSidebar',
   },
+  {
+    title: 'Subtitle Filters',
+    description: [
+      'Remove unwanted text from primary subtitles, such as speaker names, readings and sound descriptions.',
+      'Applies to the overlay, sidebar, mined sentences and stats.',
+    ],
+    notes: ['Hot-reload: filter changes apply to the current subtitle file immediately.'],
+    key: 'subtitleFilter',
+  },
 ];
 
 const INTEGRATION_TEMPLATE_SECTIONS: ConfigTemplateSection[] = [