Fix bucket permission persistence and security issues (#7226)
Security Fixes:
- Fix XSS vulnerability in showModal by using DOM methods instead of template strings for title
- Add escapeHtmlForAttribute helper to properly escape all HTML entities (&, <, >, ", ')
- Fix XSS in showSecretKey and showNewAccessKeyModal by using proper HTML escaping
- Fix XSS in createAccessKeysContent by replacing inline onclick with data attributes and event delegation
Code Cleanup:
- Remove debug label "(DEBUG)" from page header
- Remove debug console.log statements from buildBucketPermissionsNew
- Remove dead functions: addBucketPermissionRow, removeBucketPermissionRow, parseBucketPermissions, buildBucketPermissions
Validation Improvements:
- Add validation in handleUpdateUser to prevent empty permissions submission
- Update buildBucketPermissionsNew to return null when no buckets selected (instead of empty array)
- Add proper error messages for validation failures
UI Improvements:
- Enhanced access key management with proper modals and copy buttons
- Improved copy-to-clipboard functionality with fallbacks
Fixes#7226