fix: get_tools() and get_system_prompt() now read from tool_registry too

Root cause: app.py registers tools via agent._tool_registry.register()
which adds to the ToolRegistry but NOT to agent._tools (which is only
populated by use_tool() from config). Both get_tools() and
get_system_prompt() were reading only _tools, missing all post-init
registered tools. Now both methods merge _tools with
_tool_registry.list_tools().

src/agentkit/core/config_driven.py

@@ -397,8 +397,13 @@ class ConfigDrivenAgent(BaseAgent, EvolutionMixin):
                 self.use_tool(retrieve_tool)
 
     def get_tools(self) -> list[Tool]:
-        """Return registered tools for this agent."""
-        return list(self._tools)
+        """Return registered tools for this agent (from config + post-init registration)."""
+        all_tools = list(self._tools)
+        if self._tool_registry:
+            for tool in self._tool_registry.list_tools():
+                if not any(t.name == tool.name for t in all_tools):
+                    all_tools.append(tool)
+        return all_tools
 
     def get_model(self) -> str:
         """Return the LLM model name for this agent."""
@@ -416,16 +421,23 @@ class ConfigDrivenAgent(BaseAgent, EvolutionMixin):
                     parts.append(val)
 
         # Append available tools description so the LLM knows what it can use
-        if self._tools:
-            tools_desc = self._build_tools_description()
+        # Use _tool_registry (which may have tools registered post-init) as well as _tools (from config)
+        all_tools = list(self._tools)
+        if self._tool_registry:
+            for tool in self._tool_registry.list_tools():
+                if not any(t.name == tool.name for t in all_tools):
+                    all_tools.append(tool)
+        if all_tools:
+            tools_desc = self._build_tools_description(all_tools)
             parts.append(f"\n\n## 可用工具\n{tools_desc}")
 
         return "\n".join(parts) if parts else None
 
-    def _build_tools_description(self) -> str:
+    def _build_tools_description(self, tools: list | None = None) -> str:
         """Build a text description of available tools for the system prompt."""
+        tools = tools or self._tools
         lines = []
-        for tool in self._tools:
+        for tool in tools:
             lines.append(f"- **{tool.name}**: {tool.description}")
             if tool.input_schema and "properties" in tool.input_schema:
                 params = list(tool.input_schema["properties"].keys())