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.

ackit/upk.py

@@ -8,6 +8,7 @@ Patching rewrites only the blocks that contain changed bytes (stored as one LZO
 lzo.compress_stored) and moves the chunks after them; every other byte of the file stays identical.
 """
 import struct
+import threading
 from collections import OrderedDict, namedtuple
 
 from . import lzo
@@ -41,6 +42,7 @@ class Package:
             self.file_size = f.seek(0, 2)
         self._cache = OrderedDict()
         self._cache_n = cache_blocks
+        self._lock = threading.Lock()
 
     # summary -----------------------------------------------------------------------------------
     def _parse_summary(self, b, f):
@@ -157,9 +159,11 @@ class Package:
 
     # reading -----------------------------------------------------------------------------------
     def _block(self, i, f=None):
-        if i in self._cache:
-            self._cache.move_to_end(i)
-            return self._cache[i]
+        with self._lock:                        # the editor reads one package from several background jobs
+            data = self._cache.get(i)
+            if data is not None:
+                self._cache.move_to_end(i)
+                return data
         bl = self.blocks[i]
         own = f is None
         f = f or open(self.path, "rb")
@@ -169,9 +173,10 @@ class Package:
         finally:
             if own:
                 f.close()
-        self._cache[i] = data
-        if len(self._cache) > self._cache_n:
-            self._cache.popitem(last=False)
+        with self._lock:
+            self._cache[i] = data
+            if len(self._cache) > self._cache_n:
+                self._cache.popitem(last=False)
         return data
 
     def _block_index(self, off):