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/check_cjk_coverage.py

@@ -0,0 +1,64 @@
+#!/usr/bin/env python3
+"""Check which characters in translation files fall outside the font glyph ranges."""
+import json
+import unicodedata
+import glob
+import os
+
+SCRIPT_DIR = os.path.dirname(os.path.abspath(__file__))
+LANG_DIR = os.path.join(SCRIPT_DIR, '..', 'res', 'lang')
+
+# Glyph ranges from typography.cpp (regular font + CJK merge)
+RANGES = [
+    # Regular font ranges
+    (0x0020, 0x00FF),  # Basic Latin + Latin-1 Supplement
+    (0x0100, 0x024F),  # Latin Extended-A + B
+    (0x0370, 0x03FF),  # Greek and Coptic
+    (0x0400, 0x04FF),  # Cyrillic
+    (0x0500, 0x052F),  # Cyrillic Supplement
+    (0x2000, 0x206F),  # General Punctuation
+    (0x2190, 0x21FF),  # Arrows
+    (0x2200, 0x22FF),  # Mathematical Operators
+    (0x2600, 0x26FF),  # Miscellaneous Symbols
+    # CJK ranges
+    (0x2E80, 0x2FDF),  # CJK Radicals
+    (0x3000, 0x30FF),  # CJK Symbols, Hiragana, Katakana
+    (0x3100, 0x312F),  # Bopomofo
+    (0x31F0, 0x31FF),  # Katakana Extensions
+    (0x3400, 0x4DBF),  # CJK Extension A
+    (0x4E00, 0x9FFF),  # CJK Unified Ideographs
+    (0xAC00, 0xD7AF),  # Hangul Syllables
+    (0xFF00, 0xFFEF),  # Fullwidth Forms
+]
+
+def in_ranges(cp):
+    return any(lo <= cp <= hi for lo, hi in RANGES)
+
+for path in sorted(glob.glob(os.path.join(LANG_DIR, '*.json'))):
+    lang = os.path.basename(path).replace('.json', '')
+    with open(path, 'r', encoding='utf-8') as f:
+        data = json.load(f)
+
+    missing = {}
+    for key, val in data.items():
+        if not isinstance(val, str):
+            continue
+        for c in val:
+            cp = ord(c)
+            if cp > 0x7F and not in_ranges(cp):
+                if c not in missing:
+                    missing[c] = []
+                missing[c].append(key)
+
+    if missing:
+        print(f"\n=== {lang}.json: {len(missing)} missing characters ===")
+        for c in sorted(missing, key=lambda x: ord(x)):
+            cp = ord(c)
+            name = unicodedata.name(c, 'UNKNOWN')
+            keys = missing[c][:3]
+            key_str = ', '.join(keys)
+            if len(missing[c]) > 3:
+                key_str += f' (+{len(missing[c])-3} more)'
+            print(f"  U+{cp:04X} {c} ({name}) — used in: {key_str}")
+    else:
+        print(f"=== {lang}.json: OK (all characters covered) ===")