fix: point root landing page to live Swagger UI

The documentation field pointed to /api/v1/health, a dead end for
integrators looking for the API contract. Now points to
/swagger-ui/index.html, live-verified 200 after the springdoc addition
in 366f3a8.

Author: vxa8502

src/main/java/sentiment/api/RootController.java

@@ -26,7 +26,7 @@ public ResponseEntity<LandingResponse> root() {
             "live",
             "1.0.0",
             "ML-powered sentiment analysis API with negation handling",
-            "/api/v1/health"
+            "/swagger-ui/index.html"
         ));
     }
 }