feat: add test database setup and usage helpers

- Introduced a new test file for setting up an in-memory SQLite database for testing purposes.
- Added helper functions for seeding test data, including users, plans, subscriptions, and wallet transactions.
- Implemented usage helpers to load user video counts and storage usage.
- Created user payload struct and functions to build user payloads with preferences and wallet balance.
- Refactored gRPC server setup to include new services and handlers.
- Updated proto files to simplify service definitions by removing redundant service prefixes.

internal/service/usage_helpers.go

@@ -0,0 +1,29 @@
+package service
+
+import (
+	"context"
+
+	"gorm.io/gorm"
+	"stream.api/internal/database/model"
+	"stream.api/pkg/logger"
+)
+
+type usagePayload struct {
+	UserID       string `json:"user_id"`
+	TotalVideos  int64  `json:"total_videos"`
+	TotalStorage int64  `json:"total_storage"`
+}
+
+func loadUsage(ctx context.Context, db *gorm.DB, l logger.Logger, user *model.User) (*usagePayload, error) {
+	var totalVideos int64
+	if err := db.WithContext(ctx).Model(&model.Video{}).Where("user_id = ?", user.ID).Count(&totalVideos).Error; err != nil {
+		l.Error("Failed to count user videos", "error", err, "user_id", user.ID)
+		return nil, err
+	}
+
+	return &usagePayload{
+		UserID:       user.ID,
+		TotalVideos:  totalVideos,
+		TotalStorage: user.StorageUsed,
+	}, nil
+}