feat: add blob store Initialize method

apps/backend/internal/blob/fs_store.go

@@ -24,6 +24,10 @@ func NewFSStore(config FSStoreConfig) *FSStore {
 	return &FSStore{config: config}
 }
 
+func (s *FSStore) Initialize(ctx context.Context) error {
+	return os.MkdirAll(s.config.Root, 0755)
+}
+
 func (s *FSStore) GenerateUploadURL(ctx context.Context, key Key, opts UploadURLOptions) (string, error) {
 	return s.config.UploadURL, nil
 }

apps/backend/internal/blob/store.go

@@ -15,6 +15,7 @@ type UpdateOptions struct {
 }
 
 type Store interface {
+	Initialize(ctx context.Context) error
 	GenerateUploadURL(ctx context.Context, key Key, opts UploadURLOptions) (string, error)
 	Put(ctx context.Context, key Key, reader io.Reader) error
 	Update(ctx context.Context, key Key, opts UpdateOptions) error

apps/backend/internal/drexa/server.go

@@ -1,6 +1,7 @@
 package drexa
 
 import (
+	"context"
 	"fmt"
 
 	"github.com/get-drexa/drexa/internal/auth"
@@ -29,6 +30,11 @@ func NewServer(c Config) (*fiber.App, error) {
 		return nil, fmt.Errorf("unknown storage backend: %s", c.Storage.Backend)
 	}
 
+	err := blobStore.Initialize(context.Background())
+	if err != nil {
+		return nil, fmt.Errorf("failed to initialize blob store: %w", err)
+	}
+
 	// Initialize key resolver based on config
 	var keyResolver virtualfs.BlobKeyResolver
 	switch c.Storage.Mode {