Fix subtitle-cycle OSD labels and harden quality gates

- Resolve J/Shift+J subtitle-cycle OSD text via track-list labels and property expansion
- Add mpv proxy OSD runtime + regression coverage across IPC/main/runtime paths
- Scope `make pretty` to maintained source files and add scoped Prettier script
- Align release workflow with cache/install order and explicit TypeScript check
- Clean up duplicate submodule entry and remove checked-in docs/plans artifacts

scripts/prettier-scope.sh

@@ -0,0 +1,20 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+cd "$ROOT_DIR"
+
+paths=(
+  "package.json"
+  "tsconfig.json"
+  "tsconfig.renderer.json"
+  "tsconfig.typecheck.json"
+  ".prettierrc.json"
+  ".github"
+  "build"
+  "launcher"
+  "scripts"
+  "src"
+)
+
+exec bunx prettier "$@" "${paths[@]}"