Localization stage 1: stable IDs, import of tl/ translations, language picker

- every script node gets a permanent id, say nodes a Ren'Py-style tid
- all languages from the game's tl/ are imported at conversion: dialogue blocks
  matched by their source-location comment or by label + original text,
  `translate strings` become a per-language strings table
- source language from config.language or detected from the dialogue
- manifest stores locales/<lang>/<module>.json and strings.json; game.json
  lists sourceLang and available locales with progress
- player: language picker in main menu and settings, fallback to source,
  __(), [var!t] and _preferences.language
- parser: `default` with init priority, and one bad statement no longer drops
  the whole file
- docs/LOCALIZATION.md: design for translations, publishing and mods

Line endings of several converter/player files go back to LF: an earlier
commit accidentally stored them as CRLF.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

backend/tests/make_sample.py

@@ -59,6 +59,8 @@ def build(path: Path) -> Path:
     with zipfile.ZipFile(path, "w", zipfile.ZIP_DEFLATED) as zf:
         zf.writestr("SampleGame-1.0-pc/game/archive.rpa", rpa_path.read_bytes())
         zf.writestr("SampleGame-1.0-pc/game/options.rpy", options)
+        zf.writestr("SampleGame-1.0-pc/game/tl/english/script.rpy",
+                    (FIXTURES / "tl" / "english" / "script.rpy").read_bytes())
         zf.writestr("SampleGame-1.0-pc/game/audio/theme.wav", _wav())
         zf.writestr("SampleGame-1.0-pc/game/gui/main_menu.png",
                     _png((1280, 720), (30, 30, 50), "Main menu"))