feat: Implement Phase 2 cross-cutting services with email and notification enhancements

- Refactor email verification and password reset utilities to use new email service.
- Introduce email delivery queue and notification delivery model for better tracking.
- Enhance file validation and storage services for improved security and ownership management.
- Add cron job for cleaning inactive notifications with retention policy.
- Update document worker to handle document generation and storage more efficiently.
- Implement logging improvements in activity and log workers.
- Create comprehensive documentation for new API endpoints and services.
- Add unit tests for file validation and notification policies to ensure robustness.

app/models/notification/notificationDelivery.model.js

@@ -0,0 +1,11 @@
+module.exports = (sequelize, DataTypes) => sequelize.define("NotificationDelivery", {
+  id: { type: DataTypes.STRING, primaryKey: true },
+  notificationId: { type: DataTypes.STRING, allowNull: true },
+  userId: { type: DataTypes.STRING, allowNull: true },
+  channel: { type: DataTypes.ENUM("EMAIL", "PUSH"), allowNull: false },
+  recipient: { type: DataTypes.STRING, allowNull: false },
+  templateKey: { type: DataTypes.STRING, allowNull: false },
+  status: { type: DataTypes.ENUM("QUEUED", "PROCESSING", "SENT", "FAILED"), allowNull: false, defaultValue: "QUEUED" },
+  attemptCount: { type: DataTypes.INTEGER, allowNull: false, defaultValue: 0 },
+  lastAttemptAt: DataTypes.DATE, sentAt: DataTypes.DATE, failedAt: DataTypes.DATE, failureCode: DataTypes.STRING,
+}, { tableName: "notification_deliveries", timestamps: true });