docs(appframework): clarify PasswordConfirmationRequired behavior in docblocks

[joshtrichards]

• Resolves: #

Summary

Clarify the PasswordConfirmationRequired docblocks to better reflect actual middleware behavior.

Changes:

• document that password confirmation is required only when supported by the active authentication backend
• clarify that enforcement behavior is handled by the password confirmation middleware
• explain the difference between non-strict and strict modes
• document that non-strict mode relies on a recent prior confirmation
• add clearer wording for the strict constructor parameter and getStrict()

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)
• Labels added where applicable (ex: bug/enhancement, 3. to review, feature component)
• Milestone added for target branch/version (ex: 32.x for stable32)

AI (if applicable)

• The content of this PR was partly or fully generated using AI