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.

tools/check_docs.py

@@ -240,6 +240,16 @@ def catalog_claims(cat):
     west = [enc[L]["w"] for L in langs if L not in ("RUS", "JPN", "KOR", "POL")]
     claim("docs/formats/subtitles.md", "%d %% of POL are UTF-16; the other languages have %s UTF-16 strings each"
           % (pol, rng(west)))
+    utf8 = []                                  # cp1252 strings whose bytes are UTF-8 text (the game's data)
+    for L, t in sorted(texts.items()):
+        for s in t:
+            if s.enc == "a":
+                u = subtitles._encode_cp1252(s.text).decode("utf-8", "replace")
+                multi = sum(1 for c in u if ord(c) > 0x7F and c != "\ufffd")     # valid multi-byte characters
+                if multi and u.count("\ufffd") <= multi // 4:                     # (one corrupt byte tolerated)
+                    utf8.append((L, s.speech))
+    claim("docs/formats/subtitles.md", "%d cp1252 strings hold UTF-8 bytes instead (the same line in %s: `%s`"
+          % (len(utf8), ", ".join(L for L, _ in utf8), "`, `".join(sorted({sp for _, sp in utf8}))))
     with gzip.open(os.path.join(cat, subtitles.LOCATIONS), "rt", newline="") as f:
         sublocs = sum(1 for _ in csv.DictReader(f))
     claim("REPORT.md", "Edited in place in every copy (%s copies)" % n(sublocs))
@@ -505,6 +515,21 @@ def wem_claims():
           % (n(total - len(bad)), n(total), exceptions))
 
 
+def originality_claims(game):
+    """Workspace.unoriginal_files on every file with sounds or subtitles of the (original) game: no false alarm."""
+    import tempfile
+    from ackit import subtitles
+    from ackit.workspace import Workspace
+    with tempfile.TemporaryDirectory() as td:
+        ws = Workspace(game, store_root=td, archives=[game.voice_archive("INT"), "SFX", "BANK"])
+        rels = {l.file for ls in ws.catalog.locations.values() for l in ls}
+        rels |= {l.file for ls in subtitles.read_locations(os.path.join(catalog_dir(), subtitles.LOCATIONS)).values()
+                 for l in ls}
+        bad = ws.unoriginal_files([ws.bank_path(r) for r in rels])
+    claim("REPORT.md", "checked on all %s files with sounds or subtitles: %s" % (
+        n(len(rels)), "no false alarm" if not bad else "%d false alarms" % len(bad)), "Workspace.unoriginal_files")
+
+
 def test_claims():
     import subprocess
     out = subprocess.run([sys.executable, "-m", "pytest", "--collect-only", "-q", "-p", "no:cacheprovider"],
@@ -535,6 +560,7 @@ def main():
         if not game:
             raise SystemExit("--scan needs the game")
         scan_claims(game)
+        originality_claims(game)
     if a.wems:
         if not game:
             raise SystemExit("--wems needs the game")