Add admin password reset option for users (#5180)

## Summary
- add backend support for admins to reset user passwords and optionally
email notifications when SMTP is enabled
- surface mail capability in admin settings data for the UI
- add a shared change-password modal hooked into People and Team user
actions with random password generation and email options

## Testing
- not run (not requested)


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[Codex
Task](https://chatgpt.com/codex/tasks/task_b_6934b978fe3c83289b5b95dec79b3d38)

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Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

frontend/public/locales/en-GB/translation.toml

@@ -5368,6 +5368,31 @@ error = "Failed to update user status"
 success = "User deleted successfully"
 error = "Failed to delete user"
 
+[workspace.people.changePassword]
+action = "Change password"
+title = "Change password"
+subtitle = "Update the password for"
+newPassword = "New password"
+confirmPassword = "Confirm password"
+placeholder = "Enter a new password"
+confirmPlaceholder = "Re-enter the new password"
+passwordRequired = "Please enter a new password"
+passwordMismatch = "Passwords do not match"
+generateRandom = "Generate secure password"
+generatedPreview = "Generated password:"
+copyTooltip = "Copy to clipboard"
+copiedToClipboard = "Password copied to clipboard"
+copyFailed = "Failed to copy password"
+sendEmail = "Email the user about this change"
+includePassword = "Include the new password in the email"
+forcePasswordChange = "Force user to change password on next login"
+emailUnavailable = "This user's email is not a valid email address. Notifications are disabled."
+smtpDisabled = "Email notifications require SMTP to be enabled in settings."
+notifyOnly = "An email will be sent without the password, letting the user know an admin changed it."
+submit = "Update password"
+success = "Password updated successfully"
+error = "Failed to update password"
+
 [workspace.people.emailInvite]
 tab = "Email Invite"
 description = "Type or paste in emails below, separated by commas. Users will receive login credentials via email."