feat: Implement video workflow repository and related services

- Added videoWorkflowRepository with methods to manage video and user interactions.
- Introduced catalog_mapper for converting database models to protobuf representations.
- Created domain_helpers for normalizing domain and ad format values.
- Defined service interfaces for payment, account, notification, domain, ad template, player config, video, and user management.
- Implemented OAuth helpers for generating state and caching keys.
- Developed payment_proto_helpers for mapping payment-related models to protobuf.
- Added service policy helpers to enforce plan requirements and user permissions.
- Created user_mapper for converting user payloads to protobuf format.
- Implemented value_helpers for handling various value conversions and nil checks.
- Developed video_helpers for normalizing video statuses and managing storage types.
- Created video_mapper for mapping video models to protobuf format.
- Implemented render workflow for managing video creation and job processing.

internal/service/oauth_helpers.go

@@ -0,0 +1,18 @@
+package service
+
+import (
+	"crypto/rand"
+	"encoding/base64"
+)
+
+func generateOAuthState() (string, error) {
+	buffer := make([]byte, 32)
+	if _, err := rand.Read(buffer); err != nil {
+		return "", err
+	}
+	return base64.RawURLEncoding.EncodeToString(buffer), nil
+}
+
+func googleOAuthStateCacheKey(state string) string {
+	return "google_oauth_state:" + state
+}