Issue Summary

When a task checkbox is checked or unchecked on a page with view restrictions (direct or inherited from a parent page), email notifications are sent to users who do NOT have view access to that page.

Steps to Reproduce

1. Create a space restricted to specific individuals

1. Create a page with view restrictions (explicit user list)

1. Create a child page (inherits parent restrictions)

1. Add a task on the child page and assign it to User A (who has access)

1. Unassign or reassign the task (toggle the checkbox)

1. Result: User B (who does NOT have view access) receives an email notification about the task change

Expected Results

Task assignment/unassignment notifications should validate the recipient's view access before sending — consistent with how @mention notifications already suppress emails for users without page access.

Actual Results

Users without view access receive email notifications containing the task description, page title, space name, and a "View page" link they cannot access.

Workaround

n/a