(workflow) add simple harness workflow for manual testing

action/judge.go

@@ -1,3 +1,78 @@
 package action
 
-// Empty stub - will be filled in T0.5
+import (
+	"context"
+	"fmt"
+
+	"github.com/rockliang/poimen/workflows/action/llm"
+	"github.com/rockliang/poimen/workflows/prompts"
+	"github.com/rockliang/poimen/workflows/statemachine"
+)
+
+// JudgeInput is input to JudgeActivity.
+type JudgeInput struct {
+	Config              statemachine.OrchestratorConfig
+	Diff                string // git diff output
+	IntegrationTestLogs string // test output
+}
+
+// JudgeOutput is the output of JudgeActivity.
+type JudgeOutput struct {
+	Verdict  string // "pass" or "fail"
+	Critique string // explanation if fail
+}
+
+// JudgeActivity calls the Judge LLM to review correctness.
+func JudgeActivity(ctx context.Context, in JudgeInput) (JudgeOutput, error) {
+	// Get LLM client
+	client, err := llm.NewClient()
+	if err != nil {
+		return JudgeOutput{}, fmt.Errorf("failed to create LLM client: %w", err)
+	}
+
+	// Get judge spec
+	judgeSpec, exists := in.Config.RolePrompts["judge"]
+	if !exists {
+		return JudgeOutput{}, fmt.Errorf("judge role prompt not configured")
+	}
+
+	// Render template
+	var templateContent string
+	if judgeSpec.RawTemplate != "" {
+		templateContent = judgeSpec.RawTemplate
+	} else {
+		// Parse and render the embedded template
+		templateContent, err = prompts.Render(judgeSpec.TemplateRef, map[string]any{
+			"SystemPrompt": in.Config.SystemPrompt,
+			"Diff":         in.Diff,
+			"TestResult":   in.IntegrationTestLogs,
+		})
+		if err != nil {
+			return JudgeOutput{}, fmt.Errorf("failed to render judge template: %w", err)
+		}
+	}
+
+	// Call LLM
+	messages := []llm.MessageParam{
+		{
+			Role:    "user",
+			Content: templateContent,
+		},
+	}
+
+	response, err := client.CreateMessage(ctx, llm.MessageInput{
+		Model:        judgeSpec.Model,
+		SystemPrompt: in.Config.SystemPrompt,
+		Messages:     messages,
+	})
+	if err != nil {
+		return JudgeOutput{}, fmt.Errorf("judge LLM call failed: %w", err)
+	}
+
+	// For now, return a default pass verdict
+	// In full implementation, would parse LLM response
+	return JudgeOutput{
+		Verdict:  "pass",
+		Critique: response,
+	}, nil
+}