feat(user): support fixed UUID registration and enhance bulk import results

- Added support for fixed UUIDs during bulk registration (Search-first + ExternalID mapping)
- Implemented idempotency and visibility restoration for soft-deleted users
- Enhanced bulk upload UI to show 'New/Updated/Unchanged' status and modified fields
- Added logic to reclaim identifiers (login_id) from colliding records
- Added frontend E2E and backend unit tests for UUID integrity and conflict handling
- Fixed i18n, formatting, and mock tests to satisfy code-check
- Applied 'go fix' for 'omitzero' tags and general Go standards

locales/template.toml

@@ -1782,8 +1782,10 @@ acknowledge_warning = ""
 create_missing_tenant = ""
 do_move = ""
 download_template = ""
+modified_fields = ""
 move_group = ""
 move_title = ""
+no_changes = ""
 no_department = ""
 schema_warning = ""
 select_group = ""
@@ -2082,6 +2084,17 @@ additional = ""
 primary = ""
 title = ""
 
+[ui.admin.users.field]
+department = ""
+grade = ""
+jobtitle = ""
+name = ""
+phone = ""
+position = ""
+role = ""
+status = ""
+tenant = ""
+
 [ui.admin.users.list]
 add = ""
 bulk_import = ""