fix: Ensure explicit returns and correct async calls

Adds explicit `return None` statements in several functions across different modules to improve code clarity and prevent potential issues where functions might implicitly return None.
Corrects an async call in `Heartflow.deactivate_chat` by adding `await`.
Updates type hints in `heartflow_prompt_builder.py`.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/heart_flow/heartflow.py

@@ -97,6 +97,7 @@ class MaiState(enum.Enum):
             return 3
         elif self == MaiState.FOCUSED_CHAT:
             return 2
+        return None
 
     def get_focused_chat_max_num(self):
         if self == MaiState.OFFLINE:
@@ -107,6 +108,7 @@ class MaiState(enum.Enum):
             return 1
         elif self == MaiState.FOCUSED_CHAT:
             return 2
+        return None
 
 
 class MaiStateInfo:
@@ -879,7 +881,7 @@ class Heartflow:
                     if subflow.chat_state.chat_status != ChatState.ABSENT:
                         logger.debug(f"[Heartflow Deactivate] 正在将子心流 {stream_name} 状态设置为 ABSENT。")
                         # 调用 set_chat_state，它会处理日志和状态更新
-                        subflow.set_chat_state(ChatState.ABSENT)
+                        await subflow.set_chat_state(ChatState.ABSENT)
                         deactivated_count += 1
                     else:
                         # 如果已经是 ABSENT，则无需再次设置，但记录一下检查

src/plugins/heartFC_chat/heartflow_prompt_builder.py

@@ -7,7 +7,7 @@ from src.plugins.utils.chat_message_builder import build_readable_messages, get_
 from src.plugins.person_info.relationship_manager import relationship_manager
 from src.plugins.chat.utils import get_embedding, parse_text_timestamps
 import time
-from typing import Union
+from typing import Union, Optional
 from ...common.database import db
 from ..chat.utils import get_recent_group_speaker
 from ..moods.moods import MoodManager
@@ -80,12 +80,13 @@ class PromptBuilder:
 
     async def build_prompt(
         self, build_mode, reason, current_mind_info, message_txt: str, sender_name: str = "某人", chat_stream=None
-    ) -> tuple[str, str]:
+    ) -> Optional[tuple[str, str]]:
         if build_mode == "normal":
             return await self._build_prompt_normal(chat_stream, message_txt, sender_name)
 
         elif build_mode == "focus":
             return await self._build_prompt_focus(reason, current_mind_info, chat_stream, message_txt, sender_name)
+        return None
 
     async def _build_prompt_focus(
         self, reason, current_mind_info, chat_stream, message_txt: str, sender_name: str = "某人"

src/plugins/models/utils_model.py

@@ -689,7 +689,7 @@ class LLMRequest:
         stream_mode = request_content["stream_mode"]
         if response.status in policy["retry_codes"] or response.status in policy["abort_codes"]:
             await self._handle_error_response(response, retry_count, policy)
-            return
+            return None
 
         response.raise_for_status()
         result = {}