feat: replace wanakana with english-to-kana 49K dictionary

- Vendor english-kana-matcher.js (english-to-kana, MIT, 49216 words)
- Rewrite bridge: dictionary lookup + letter-by-letter fallback for OOV words
- Convert English punctuation (,.!?) to Japanese pauses (、。)
- Fix Chinese fullwidth comma being stripped by filter_kana
- Preserve decimal points in numbers (3.5 -> スリーファイブ)
- main.py now applies filter_kana (matches web UI behavior)
- Remove wanakana dependency; rebuild portable zip (82.5 MB)

chinese2kana.py

@@ -16,7 +16,7 @@ _KANA_SAFE_RE = re.compile(
     r"\u3001\u3002\uFF01\uFF1F"
     r"\u300C\u300D"
     r"\u30FB\u3000"
-    r"a-zA-Z0-9 ]"
+    r"a-zA-Z0-9 ,.!?\uFF0C]"
 )
 
 _CHINESE_DIGITS = ["零", "一", "二", "三", "四", "五", "六", "七", "八", "九"]
@@ -85,7 +85,7 @@ def chinese_to_kana(text: str, convert_numbers: bool = True) -> str:
         else:
             result_parts.append(seg)
     result = "".join(result_parts)
-    result = re.sub(r"(?<=\S) (?=\S)", "", result)
+    result = re.sub(r"(?<=[^\x00-\x7F]) (?=[^\x00-\x7F])", "", result)
     return result