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/node_template.py

@@ -2,7 +2,7 @@
 节点模板模型
 用于管理和复用LLM节点的提示词模板
 """
-from sqlalchemy import Column, String, Text, Integer, DateTime, JSON, ForeignKey, Boolean, func
+from sqlalchemy import Column, String, Text, Integer, DateTime, JSON, ForeignKey, Boolean, Index, func
 from sqlalchemy.dialects.mysql import CHAR
 from sqlalchemy.orm import relationship
 from app.core.database import Base
@@ -37,6 +37,12 @@ class NodeTemplate(Base):
     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")
 
+    __table_args__ = (
+        Index("idx_nt_category", "category"),
+        Index("idx_nt_user_id", "user_id"),
+        Index("idx_nt_is_public", "is_public"),
+    )
+
     # 关系
     user = relationship("User", backref="node_templates")