feat: CJK font rendering, force quit confirmation, settings i18n

- Rebuild CJK font subset (1421 glyphs) and convert CFF→TTF for
  stb_truetype compatibility, fixing Chinese/Japanese/Korean rendering
- Add force quit confirmation dialog with cancel/confirm actions
- Show force quit tooltip immediately on hover (no delay)
- Translate hardcoded English strings in settings dropdowns
  (auto-lock timeouts, slider "Off" labels)
- Fix mojibake en-dashes in 7 translation JSON files
- Add helper scripts: build_cjk_subset, convert_cjk_to_ttf,
  check_font_coverage, fix_mojibake

scripts/fix_mojibake.py

@@ -0,0 +1,36 @@
+#!/usr/bin/env python3
+"""Fix mojibake en-dash (and other common patterns) in translation JSON files."""
+import os
+import glob
+
+LANG_DIR = os.path.join(os.path.dirname(os.path.dirname(os.path.abspath(__file__))), 'res', 'lang')
+
+# Common mojibake patterns: UTF-8 bytes interpreted as Latin-1
+MOJIBAKE_FIXES = {
+    '\u00e2\u0080\u0093': '\u2013',  # en dash
+    '\u00e2\u0080\u0094': '\u2014',  # em dash
+    '\u00e2\u0080\u0099': '\u2019',  # right single quote
+    '\u00e2\u0080\u009c': '\u201c',  # left double quote
+    '\u00e2\u0080\u009d': '\u201d',  # right double quote
+    '\u00e2\u0080\u00a6': '\u2026',  # ellipsis
+}
+
+total_fixed = 0
+for path in sorted(glob.glob(os.path.join(LANG_DIR, '*.json'))):
+    with open(path, 'r', encoding='utf-8') as f:
+        raw = f.read()
+
+    original = raw
+    for bad, good in MOJIBAKE_FIXES.items():
+        if bad in raw:
+            count = raw.count(bad)
+            raw = raw.replace(bad, good)
+            lang = os.path.basename(path)
+            print(f"  {lang}: fixed {count} x {repr(good)}")
+            total_fixed += count
+
+    if raw != original:
+        with open(path, 'w', encoding='utf-8') as f:
+            f.write(raw)
+
+print(f"\nTotal fixes: {total_fixed}")