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/knowledge_entry.py

@@ -12,6 +12,7 @@ class KnowledgeEntry(Base):
     __tablename__ = "knowledge_entries"
 
     id = Column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
+    agent_id = Column(String(36), nullable=True, index=True, comment="所属 Agent ID（NULL=全Agent共享）")
     title = Column(String(500), nullable=False, comment="知识标题（一句话概括）")
     category = Column(String(30), nullable=False, index=True,
                       comment="类别: bug_fix/best_practice/workaround/optimization/insight")
@@ -44,7 +45,6 @@ class KnowledgeEntry(Base):
     updated_at = Column(DateTime, default=datetime.now, onupdate=datetime.now, comment="更新时间")
 
     __table_args__ = (
-        Index("ix_knowledge_entries_category", "category"),
         Index("ix_knowledge_entries_active", "is_active"),
     )
 
@@ -54,6 +54,7 @@ class KnowledgeEntry(Base):
     def to_dict(self) -> dict:
         return {
             "id": self.id,
+            "agent_id": self.agent_id,
             "title": self.title,
             "category": self.category,
             "tags": self.tags or [],