fix: delete agent 500 error + dynamic personality + deployment guide

- Fix delete agent 500: clean up FK records (agent_llm_logs, permissions,
  schedules, executions, team_members) and unbind goals/tasks before delete
- Remove hardcoded personality templates in Android, replace with dynamic
  system prompt generation from name + description
- Set promptSectionsEnabled=false to bypass PromptComposer for personality
- Add Tencent Cloud Linux deployment guide (Docker Compose)
- Accumulated backend service updates, frontend UI fixes, Android app changes

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/app/models/model_config.py

@@ -1,7 +1,7 @@
 """
 模型配置模型
 """
-from sqlalchemy import Column, String, DateTime, ForeignKey, func
+from sqlalchemy import Column, String, DateTime, ForeignKey, Index, func
 from sqlalchemy.dialects.mysql import CHAR
 from sqlalchemy.orm import relationship
 from app.core.database import Base
@@ -19,11 +19,16 @@ class ModelConfig(Base):
     api_key = Column(String(500), nullable=False, comment="API密钥（加密存储）")
     base_url = Column(String(255), comment="API地址")
     user_id = Column(CHAR(36), ForeignKey("users.id"), comment="所属用户ID")
+    workspace_id = Column(CHAR(36), ForeignKey("workspaces.id"), nullable=True, comment="所属工作区ID")
     created_at = Column(DateTime, default=func.now(), comment="创建时间")
     updated_at = Column(DateTime, default=func.now(), onupdate=func.now(), comment="更新时间")
 
     # 关系
     user = relationship("User", backref="model_configs")
 
+    __table_args__ = (
+        Index("ix_model_configs_workspace", "workspace_id"),
+    )
+
     def __repr__(self):
         return f"<ModelConfig(id={self.id}, name={self.name}, provider={self.provider})>"