feat: add registry repair framework

- add shared registry validation service
- add transaction-safe repair CLI
- refactor doctor to use validator
- improve restore integrity checks
- add registry repair integration tests
- strengthen global slug consistency

src/services/mod.rs

@@ -3,4 +3,5 @@ pub mod audit;
 pub mod bulk;
 pub mod landing_pages;
 pub mod qr;
+pub mod registry_validator;
 pub mod shortener;