fix: center the update action tooltip

Remove the duplicate native title tooltip and center the single custom update hint directly below the available-update action.

renderer/styles.css

@@ -2172,7 +2172,8 @@ select.hs-input { max-width: none; width: auto; min-width: 140px; }
   content: attr(data-tooltip);
   position: absolute;
   top: calc(100% + 10px);
-  right: 0;
+  left: 50%;
+  right: auto;
   width: max-content;
   max-width: min(240px, calc(100vw - 24px));
   padding: 8px 10px;
@@ -2188,7 +2189,7 @@ select.hs-input { max-width: none; width: auto; min-width: 140px; }
   white-space: normal;
   opacity: 0;
   pointer-events: none;
-  transform: translateY(-3px);
+  transform: translate(-50%, -3px);
   transition: opacity .14s, transform .14s;
   z-index: 80;
 }
@@ -2196,7 +2197,7 @@ select.hs-input { max-width: none; width: auto; min-width: 140px; }
 .header-update-button:hover::after,
 .header-update-button:focus-visible::after {
   opacity: 1;
-  transform: translateY(0);
+  transform: translate(-50%, 0);
 }
 
 .header-update-button:hover {