Chinese main menu: font atlas + GB2312 tables + Strings translation

- build_cjk.py: 2048x1024 UI atlas (original ASCII at 0,0 + full GB2312 at 12px) and
  cjk_glyph/cjk_metric tables.
- cn_strings.py + make_cn_strings.py: escape-aware GB2312 rewrite of Strings.dat (46 entries).
- install_cjk.py: one-shot deploy/restore (exe patch, atlas loose+res, strings).
- apply_cjk.py: fix metrics cave code byte order (was (second<<8)|first) so CJK width
  measures correctly and centred labels are no longer flushed right.
- docs: DEVLOG + patch notes for the atlas and the fix.

.gitignore

@@ -7,6 +7,10 @@
 !/.gitignore
 !/README.md
 
+# Python caches
+__pycache__/
+*.pyc
+
 # Belt-and-suspenders: never track game / crack / media / build artifacts
 *.res
 *.iso