fix: 翻译功能的一些小优化和修复 (#1225)

1. llm温度是可调的，对于ds而言，翻译1.3最佳，默认值调整成该值
2. 翻译字典，最多允许从50增加到80，取头尾各一半，因为小说出场最早和最近的人最重要

Co-authored-by: duanhl <duanhl7749@gmail.com>

app/src/main/res/values/strings.xml

@@ -1709,6 +1709,8 @@
     <string name="llm_max_chars_per_chunk">Max Chars Per Chunk</string>
     <string name="llm_concurrent_chunks">Concurrent Chunks</string>
     <string name="llm_retry_count">Retry Count</string>
+    <string name="llm_temperature">Temperature</string>
+    <string name="llm_temperature_description">Allowed range: 0-2. Closer to 0 is stricter; closer to 2 is more creative.</string>
     <string name="translation_prompt">Translation Prompt</string>
     <string name="llm_prompt">Prompt</string>
     <string name="translate_chapter">Translate Chapter</string>