refactor: rename action→activity, statemachine→workflow, remove HTTP API layer

- action/ → activity/ (Temporal activities)
- statemachine/ → workflow/ (Temporal workflows)
- Removed internal/api/ and cmd/server/ (api-gw handles HTTP, Temporal is the API)
- Created pkg/types/types.go as single source of truth for all shared types
- Extracted CallRoleLLM helper (DRY: implementer/planner/judge shared pattern)
- Fixed circular import: workflow_graph_query uses string activity names
- Fixed logger.logf → logger.Info/Warn (method didn't exist)
- Fixed routing types: added Branches, Activity, BackoffSeconds, TaskActivity
- Fixed db.Canvas.Name, db.Client→DB, GetWorkflow→FetchWorkflow
- Removed unused imports
- All tests pass, build clean, vet clean

cmd/starter/main.go

@@ -11,12 +11,12 @@ import (
 	"time"
 
 	"go.temporal.io/sdk/client"
-	"github.com/rockliang/poimen/workflows/action/llm"
+	"github.com/rockliang/poimen/workflows/activity/llm"
 	"github.com/rockliang/poimen/workflows/internal/config"
 	"github.com/rockliang/poimen/workflows/internal/health"
 	"github.com/rockliang/poimen/workflows/internal/logging"
 	"github.com/rockliang/poimen/workflows/internal/routing"
-	"github.com/rockliang/poimen/workflows/statemachine"
+	"github.com/rockliang/poimen/workflows/workflow"
 )
 
 func main() {
@@ -89,20 +89,20 @@ func main() {
 
 
 	// Build OrchestratorInput
-	input := statemachine.OrchestratorInput{
+	input := workflow.OrchestratorInput{
 		TargetRepoPath:     *repoPath,
 		RemoteURL:          *remoteURL,
 		Milestone:          *milestone,
 		DryRun:             *dryRun,
 		MaxCyclesBeforeCAN: 100,
 		PiProvider:         *piProvider,
-		Config: statemachine.OrchestratorConfig{
+		Config: workflow.OrchestratorConfig{
 			SystemPrompt: "You are an expert software developer orchestrating multi-agent work.",
-			Skills:       []statemachine.SkillRef{},
-			RolePrompts: map[string]statemachine.PromptSpec{
+			Skills:       []workflow.SkillRef{},
+			RolePrompts: map[string]workflow.PromptSpec{
 				"planner": {
 					TemplateRef: "planner/default.tmpl",
-					Model: statemachine.ModelSpec{
+					Model: workflow.ModelSpec{
 						ModelID:  *plannerModel,
 						Thinking: "adaptive",
 						Effort:   "high",
@@ -110,7 +110,7 @@ func main() {
 				},
 				"judge": {
 					TemplateRef: "judge/default.tmpl",
-					Model: statemachine.ModelSpec{
+					Model: workflow.ModelSpec{
 						ModelID:  *judgeModel,
 						Thinking: "adaptive",
 						Effort:   "high",
@@ -118,12 +118,12 @@ func main() {
 				},
 				"implementer": {
 					TemplateRef: "implementer/default.tmpl",
-					Model: statemachine.ModelSpec{
+					Model: workflow.ModelSpec{
 						ModelID: *implementerModel,
 					},
 				},
 			},
-			Tuning: statemachine.NewActivityTuning(),
+			Tuning: workflow.NewActivityTuning(),
 		},
 	}
 
@@ -144,7 +144,7 @@ func main() {
 	run, err := c.ExecuteWorkflow(context.Background(), client.StartWorkflowOptions{
 		ID:        workflowID,
 		TaskQueue: "poimen-taskqueue",
-	}, statemachine.OrchestratorWorkflow, input)
+	}, workflow.OrchestratorWorkflow, input)
 	if err != nil {
 		logging.Fatal("failed to start workflow", logging.Err(err))
 	}
@@ -164,7 +164,7 @@ func main() {
 	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Minute)
 	defer cancel()
 
-	var result statemachine.OrchestratorOutput
+	var result workflow.OrchestratorOutput
 	if err := run.Get(ctx, &result); err != nil {
 		fmt.Printf("\nWorkflow initiated (execution in progress).\n")
 		fmt.Printf("Check the Web UI for real-time status updates.\n")
@@ -267,12 +267,12 @@ func runRoutingWorkflow(c client.Client, routeMsg, specFile string, isCron, dryR
 	}
 
 	workflowID := "routing-" + spec.Name + "-" + time.Now().Format("20060102-150405")
-	input := statemachine.RoutingWorkflowInput{Spec: spec}
+	input := workflow.RoutingWorkflowInput{Spec: spec}
 
 	run, err := c.ExecuteWorkflow(ctx, client.StartWorkflowOptions{
 		ID:        workflowID,
 		TaskQueue: "poimen-taskqueue",
-	}, statemachine.RoutingWorkflow, input)
+	}, workflow.RoutingWorkflow, input)
 	if err != nil {
 		logging.Fatal("failed to start routing workflow", logging.Err(err))
 	}
@@ -285,7 +285,7 @@ func runRoutingWorkflow(c client.Client, routeMsg, specFile string, isCron, dryR
 	waitCtx, cancel := context.WithTimeout(ctx, 30*time.Second)
 	defer cancel()
 
-	var result statemachine.RoutingWorkflowOutput
+	var result workflow.RoutingWorkflowOutput
 	if err := run.Get(waitCtx, &result); err != nil {
 		fmt.Printf("\nWorkflow running (check Temporal UI for status)\n")
 	} else {