fix: right-align prompt enhance and send buttons in chat input

Add margin-left: auto and flex-shrink: 0 to .prompt-input-hint-actions
so the enhance and send/stop buttons always stay right-aligned regardless
of selector content width. Add min-width: 0 and overflow: hidden to
.prompt-input-hint-selectors to prevent them from pushing the action
buttons off-screen when model names or reasoning toggles are wide.

packages/kilo-vscode/webview-ui/src/styles/chat.css

@@ -363,6 +363,8 @@
   display: flex;
   flex-wrap: wrap;
   gap: 4px;
+  min-width: 0;
+  overflow: hidden;
 
   [data-component="button"] {
     height: auto !important;
@@ -400,6 +402,8 @@
 .prompt-input-hint-actions {
   display: flex;
   gap: 4px;
+  margin-left: auto;
+  flex-shrink: 0;
 
   [data-component="button"] {
     background: transparent;