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

internal/routing/llm_client.go

@@ -8,7 +8,6 @@ import (
 	"io"
 	"net/http"
 	"os"
-	"strings"
 )
 
 var (

internal/routing/types.go

@@ -28,12 +28,16 @@ type State struct {
 	Type              StateType `json:"type"`
 	
 	// Task fields
+	Activity          string                 `json:"activity,omitempty"`
 	Resource          string                 `json:"resource,omitempty"`
 	Parameters        map[string]interface{} `json:"parameters,omitempty"`
 	Timeout           string                 `json:"timeout,omitempty"`
 	Retry             *RetryPolicy           `json:"retry,omitempty"`
 	Catch             []CatchClause          `json:"catch,omitempty"`
 	
+	// Parallel fields
+	Branches          []interface{}          `json:"branches,omitempty"`
+	
 	// Pass fields
 	Result            interface{} `json:"result,omitempty"`
 	
@@ -50,14 +54,18 @@ type State struct {
 type StateType string
 
 const (
-	StateTypeTask StateType = "Task"
-	StateTypePass StateType = "Pass"
-	StateTypeFail StateType = "Fail"
+	StateTypeTask     StateType = "Task"
+	StateTypePass     StateType = "Pass"
+	StateTypeFail     StateType = "Fail"
+	StateTypeParallel StateType = "Parallel"
+
+	TaskActivity = "Task"
 )
 
 // RetryPolicy defines retry behavior for activities
 type RetryPolicy struct {
 	MaxAttempts     int32   `json:"maxAttempts"`
+	BackoffSeconds  int32   `json:"backoffSeconds,omitempty"`
 	BackoffRate     float64 `json:"backoffRate"`
 	InitialInterval string  `json:"initialInterval"`
 	MaxInterval     string  `json:"maxInterval,omitempty"`