refactor: adopt PathRegistry in execution/setup.go

Update internal/worker/execution/setup.go to use centralized PathRegistry:

Changes:
- Add import for internal/config package
- Update SetupJobDirectories to use config.FromEnv() for directory creation
- Replace all os.MkdirAll calls with paths.EnsureDir()
  - pendingDir creation
  - jobDir creation
  - outputDir (running) creation

Benefits:
- Consistent directory creation via PathRegistry
- Centralized path management for job execution directories
- Better error handling for directory creation failures

internal/worker/execution/setup.go

@@ -8,6 +8,7 @@ import (
 	"path/filepath"
 	"strings"
 
+	"github.com/jfraeys/fetch_ml/internal/config"
 	"github.com/jfraeys/fetch_ml/internal/container"
 	"github.com/jfraeys/fetch_ml/internal/errtypes"
 	"github.com/jfraeys/fetch_ml/internal/storage"
@@ -20,7 +21,7 @@ type JobPaths struct {
 	LogFile   string
 }
 
-// SetupJobDirectories creates the necessary directories for a job
+// SetupJobDirectories creates the necessary directories for a job using PathRegistry
 func SetupJobDirectories(
 	basePath string,
 	jobName string,
@@ -32,8 +33,11 @@ func SetupJobDirectories(
 	outputDir = filepath.Join(jobPaths.RunningPath(), jobName)
 	logFile = filepath.Join(outputDir, "output.log")
 
+	// Use PathRegistry for consistent directory creation
+	paths := config.FromEnv()
+
 	// Create pending directory
-	if err := os.MkdirAll(pendingDir, 0750); err != nil {
+	if err := paths.EnsureDir(pendingDir); err != nil {
 		return "", "", "", &errtypes.TaskExecutionError{
 			TaskID:  taskID,
 			JobName: jobName,
@@ -43,7 +47,7 @@ func SetupJobDirectories(
 	}
 
 	// Create job directory in pending
-	if err := os.MkdirAll(jobDir, 0750); err != nil {
+	if err := paths.EnsureDir(jobDir); err != nil {
 		return "", "", "", &errtypes.TaskExecutionError{
 			TaskID:  taskID,
 			JobName: jobName,
@@ -73,7 +77,7 @@ func SetupJobDirectories(
 	}
 
 	// Create running directory
-	if err := os.MkdirAll(outputDir, 0750); err != nil {
+	if err := paths.EnsureDir(outputDir); err != nil {
 		return "", "", "", &errtypes.TaskExecutionError{
 			TaskID:  taskID,
 			JobName: jobName,