Fix SSE route dependency and align architecture docs

backend/app/utils/chunking.py

@@ -1,19 +1,25 @@
+"""Provide utility helpers for chunking."""
+
 import re
 from typing import List
 from app.core.config import settings
+# Keep module behavior explicit so the backend flow stays easy to audit.
+
 
 
 class TextChunker:
+    """Represent the Text Chunker type."""
     def __init__(
         self,
         chunk_size: int = settings.chunk_size,
         chunk_overlap: int = settings.chunk_overlap,
     ):
+        """Initialize the Text Chunker instance."""
         self.chunk_size = chunk_size
         self.chunk_overlap = chunk_overlap
 
     def chunk_by_clause(self, text: str) -> List[dict]:
-        """按条款边界分块（适用于法规文档）"""
+        """Handle chunk by clause for the Text Chunker instance."""
         clause_pattern = r"(第[一二三四五六七八九十百]+条)"
         parts = re.split(clause_pattern, text)
 
@@ -46,7 +52,7 @@ class TextChunker:
         return chunks
 
     def chunk_by_size(self, text: str) -> List[dict]:
-        """按固定大小分块"""
+        """Handle chunk by size for the Text Chunker instance."""
         chunks = []
         start = 0
         chunk_index = 0
@@ -69,7 +75,7 @@ class TextChunker:
         return chunks
 
     def estimate_tokens(self, text: str) -> int:
-        """估算token数量"""
+        """Handle estimate tokens for the Text Chunker instance."""
         chinese_chars = len(re.findall(r"[^\x00-\xff]", text))
         english_chars = len(text) - chinese_chars
         return int(chinese_chars / 1.5 + english_chars / 4)