feat(loop): agent loop（8 轮 + checkpoint + 流式 + 记忆注入/提取 + trace + 工具超时回喂）

internal/runtime/loop/stream.go

@@ -0,0 +1,57 @@
+package loop
+
+import (
+	"context"
+	"fmt"
+
+	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/agent"
+	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/model"
+)
+
+// streamStep drives a streaming model call. It is the streaming counterpart of
+// agent.RunStep: it builds the request from the agent's public surface, runs the
+// loop's input guardrail, streams deltas through OnStream, runs the output
+// guardrail and decodes any tool calls. Because RunStep does not expose a stream
+// path, this method is owned by the loop; it mirrors the agent's semantics so the
+// two behave identically apart from the delta callback.
+func (l *Loop) streamStep(ctx context.Context, messages []model.Message) (*stepOutcome, error) {
+	adapter := l.agent.Adapter()
+	if adapter == nil {
+		return nil, fmt.Errorf("loop: stream step: %w", ErrNoAdapter)
+	}
+	req := l.buildRequest(messages)
+
+	if l.guards != nil {
+		verdict, err := l.guards.CheckInput(ctx, &req)
+		if err != nil {
+			return nil, fmt.Errorf("loop: check input: %w", err)
+		}
+		if verdict != nil && !verdict.Allow {
+			return &stepOutcome{final: true, text: verdict.Reason, stopReason: agent.StopReasonGuardrailInput}, nil
+		}
+	}
+
+	resp, err := adapter.ChatStream(ctx, req, func(delta string) {
+		if l.onStream != nil {
+			l.onStream(delta)
+		}
+	})
+	if err != nil {
+		return nil, fmt.Errorf("loop: chat stream: %w", err)
+	}
+
+	if l.guards != nil {
+		verdict, err := l.guards.CheckOutput(ctx, &resp)
+		if err != nil {
+			return nil, fmt.Errorf("loop: check output: %w", err)
+		}
+		if verdict != nil && !verdict.Allow {
+			return &stepOutcome{final: true, text: verdict.Reason, stopReason: agent.StopReasonGuardrailOutput}, nil
+		}
+	}
+
+	if calls, ok := decodeToolCalls(resp); ok {
+		return &stepOutcome{final: false, toolCalls: calls, stopReason: agent.StopReasonToolCalls}, nil
+	}
+	return &stepOutcome{final: true, text: resp.Content, stopReason: agent.StopReasonStop}, nil
+}