feat(overlay): add optional subtitle selection modal

- Add primary and secondary mpv track selection from the overlay
- Support configurable sequence shortcuts with conflict detection and hot reload
- Document settings, shortcuts, and generated config defaults

src/config/resolve/core-domains.ts

@@ -6,6 +6,25 @@ import { asBoolean, asNumber, asString, isObject } from './shared';
 export function applyCoreDomainConfig(context: ResolveContext): void {
   const { src, resolved, warn } = context;
 
+  if (isObject(src.subtitleSelection)) {
+    const enabled = asBoolean(src.subtitleSelection.enabled);
+    if (enabled !== undefined) resolved.subtitleSelection.enabled = enabled;
+    else if (src.subtitleSelection.enabled !== undefined)
+      warn(
+        'subtitleSelection.enabled',
+        src.subtitleSelection.enabled,
+        resolved.subtitleSelection.enabled,
+        'Expected boolean.',
+      );
+  } else if (src.subtitleSelection !== undefined) {
+    warn(
+      'subtitleSelection',
+      src.subtitleSelection,
+      resolved.subtitleSelection,
+      'Expected object.',
+    );
+  }
+
   if (isObject(src.texthooker)) {
     const launchAtStartup = asBoolean(src.texthooker.launchAtStartup);
     if (launchAtStartup !== undefined) {
@@ -237,6 +256,7 @@ export function applyCoreDomainConfig(context: ResolveContext): void {
       'openRuntimeOptions',
       'openJimaku',
       'openTsukihime',
+      'openSubtitleSelection',
       'openSubtitleGeneration',
       'openSessionHelp',
       'openControllerSelect',