Full correctness check against the docs: safer writes, reverts and texts

Safety
- Writes are serialized (Workspace.lock): two background jobs rebuilding one
  package (a sound and its subtitle applied side by side) lost an edit.
- A store copies a bank file or package as "original" only if it matches the
  shipped catalog (Workspace.unoriginal_files: in-memory sounds, bank copies of
  voice lines, subtitles); the editor refuses to switch stores while changes
  are applied. A second store could otherwise resurrect a reverted sound.
- Mod import in the editor asks before overwriting files changed outside the
  tool (it forced silently).
- Revert all in the editor reverts texts too; the uninstaller counts text
  edits before offering to delete the store.
- ackit restore-backup: the full-backup restore decisions.md described; it
  keeps the sounds of WADs without a full copy recorded.
- build_catalog also stops when a subtitle differs from the catalog.

Languages and texts
- Game.language() returns languages without voices (JPN, RUS, ...) and
  Game.voice_archive() their INT voices; ackit text --lang JPN works.
- Menu lookups parse one cached file (find & replace: minutes -> ms).
- Subtitles decode cp1252 as Windows does: the UTF-8-in-cp1252 line
  Speech_TAPE_J_Answer_1_00 (KOR/POL/POR/RUS) is written back byte-for-byte;
  SUB_KOR/SUB_RUS rebuilt from the original game (only those rows changed).
- Mods exported while another language is loaded keep name and line.

Other fixes
- Down-mix folds extra channels in at -3 dB (a 5.1 centre voice was dropped).
- e2e_editor no longer overwrites the user's settings.json; kill_game waits
  for the game to exit before reverts.
- Recorder handles Int32/UInt8 input and split frames; package block cache
  locked; conflict messages, CLI help examples, stale docstrings and doc
  references fixed; tests no longer read this PC's game language.

Docs (decisions, user guide, README, subtitles.md, banks.md, catalog README,
REPORT, NOTES, CLAUDE.md) updated; check_docs: 102 claims match. 148 tests;
e2e_features 9/9, e2e_editor and verify PASS; game original afterwards.

tests/test_texts.py

@@ -1,5 +1,6 @@
 """Subtitles (dialogue objects in packages) and menu text (localization files): parse, apply, revert."""
 import hashlib
+import struct
 import os
 
 import pytest
@@ -36,6 +37,10 @@ def test_fstring_encoding():
         subtitles.encode_fstring("too long", 10, "a")
     with pytest.raises(subtitles.SubtitleError):
         subtitles.encode_fstring("→", 10, "a")                      # not in cp1252
+    # every byte reads back as it was, also the 5 that Python's cp1252 leaves undefined (UTF-8 in two game strings)
+    raw = struct.pack("<i", 7) + "Уж".encode("utf-8") + b"\x81\x8d\0"
+    text = subtitles.read_fstring(raw, 0)[0]
+    assert subtitles.encode_fstring(text, len(raw), "a") == raw
 
 
 def test_menu_parse_and_write():
@@ -51,6 +56,15 @@ def test_menu_parse_and_write():
         loctext.write(raw, "INT", fname, {"INT:FRONTEND.int:Menu:Start": "two\nlines"})
 
 
+def test_menu_check_value():
+    loctext.check_value("Fine", "utf-16", "F.int")
+    loctext.check_value("Città", "cp1252", "F.int")
+    with pytest.raises(loctext.TextError):
+        loctext.check_value("two\nlines", "utf-16", "F.int")
+    with pytest.raises(loctext.TextError):
+        loctext.check_value("Привет", "cp1252", "F.int")                # not in the file's encoding
+
+
 # --- subtitles through the workspace ------------------------------------------------------------
 def test_subtitle_catalog_and_link(synth_game, tmp_path):
     root, _ = synth_game