fix(lyric_translator): add readme and add async request

app/services/lyric_romanji_translator.py

@@ -1,8 +1,10 @@
 import os
 import re
+import asyncio
 from app.core.deepseek_client import chat_with_openai
 from app.models.lyric_romanji_translator import FileResult
 
+semaphore = asyncio.Semaphore(5)
 timestamp_pattern = re.compile(r"^\[\d{2}:\d{2}\.\d{2}\]")
 
 def needs_romaji(lines, idx):
@@ -39,21 +41,28 @@ async def process_lrc_file(filepath: str) -> FileResult:
 
     return FileResult(file=filepath, processed=added_lines > 0, added_lines=added_lines)
 
+async def safe_process(filepath):
+    async with semaphore:
+        print(f"Processing: {filepath}")
+        return await process_lrc_file(filepath)
+
 async def translate_lyric_romanji(folder_path: str):
     results = []
 
     if not os.path.exists(folder_path):
         return {"results": [], "status": f"error: folder not found {folder_path}"}
 
+    tasks = []
     for root, _, files in os.walk(folder_path):
         for file in files:
             if file.endswith(".lrc"):
                 filepath = os.path.join(root, file)
-                print(f"Processing: {filepath}")
+                tasks.append(asyncio.create_task(safe_process(filepath)))
 
-                result = await process_lrc_file(filepath)
+    if not tasks:
+        return {"results": [], "status": "no .lrc files found"}
 
-                # ✅ result is already a FileResult object
-                results.append(result)
+    # Run them all concurrently
+    results = await asyncio.gather(*tasks)
 
     return {"results": results, "status": "completed"}