[codex] Replace mpv fullscreen toggle with launch mode config (#48)

Co-authored-by: bee <autumn@skerritt.blog>

launcher/config/mpv-config.ts

@@ -0,0 +1,12 @@
+import { parseMpvLaunchMode } from '../../src/shared/mpv-launch-mode.js';
+import type { LauncherMpvConfig } from '../types.js';
+
+export function parseLauncherMpvConfig(root: Record<string, unknown>): LauncherMpvConfig {
+  const mpvRaw = root.mpv;
+  if (!mpvRaw || typeof mpvRaw !== 'object') return {};
+  const mpv = mpvRaw as Record<string, unknown>;
+
+  return {
+    launchMode: parseMpvLaunchMode(mpv.launchMode),
+  };
+}