Add shared password update notification setting

[66Ton99]

Summary

• Add self-notification toggles for password and folder update/delete emails.
• Keep the existing global update/delete notification toggles as the primary subscription gates.
• Update notification subjects/templates so operators receive “You ...” wording when self-notifications are enabled.
• Add coverage for default settings, form validation, resource notifications, folder notifications, and locale strings.

[CLAassistant]

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