Fix foreign key relationship in NotificationSettings table

[dkhalife]

It should be possible to delete a user and have all their data deleted through cascades.

[Copilot]

Pull Request Overview

This PR aims to fix the foreign key relationship in the NotificationSettings table by removing the direct foreign key reference and instead linking NotificationSettings through the associated User. Key changes include:

• Removing the direct NotificationSettings foreign key from the Notification model.
• Adding cascade deletion constraints to the Task and User relations.
• Updating queries and notification sending logic to reference NotificationSettings via the User association.

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
internal/models/notification.go	Removed NotificationSettings relationship and added cascade constraints for Task and User
internal/services/notifications/notifications.go	Updated notification provider lookups to reference NotificationSettings via User
internal/repos/notifier/notifier.go	Modified Preload to load NotificationSettings nested under User

Comments suppressed due to low confidence (3)

internal/models/notification.go:15

• The direct foreign key relationship for NotificationSettings is removed; ensure that all related logic is updated to use the User association for accessing NotificationSettings.

-	NotificationSettings NotificationSettings `json:"-" gorm:"foreignKey:UserID;references:UserID"`

internal/services/notifications/notifications.go:16

• [nitpick] The nested use of 'Provider.Provider' may be confusing; consider renaming the inner field to clearly differentiate between the provider's type and its configuration.

switch notification.User.NotificationSettings.Provider.Provider {

internal/repos/notifier/notifier.go:86

• Ensure that preloading 'User.NotificationSettings' fully covers the required associations after the foreign key change; verify that no unintended gaps exist in the data loading.

if err := r.db.Where("is_sent = 0 AND scheduled_for < ?", cutoff).Preload("User.NotificationSettings").Find(&notifications).Error; err != nil {