refactor(vscode): clarify prompt rail edge intent

packages/kilo-vscode/src/KiloProvider.ts

@@ -5321,6 +5321,7 @@ export class KiloProvider implements vscode.WebviewViewProvider, TelemetryProper
 
   private _getHtmlForWebview(webview: vscode.Webview, sidebar = false): string {
     return buildWebviewHtml(webview, {
+      // The rail follows the physical workbench edge. RTL text direction must not move it between chat and code.
       sidebar: sidebar
         ? vscode.workspace.getConfiguration("workbench").get("sideBar.location") === "right"
           ? "right"

packages/kilo-vscode/webview-ui/src/components/chat/MessageList.tsx

@@ -1376,6 +1376,7 @@ export const MessageList: Component<MessageListProps> = (props) => {
       </div>
 
       <PromptRail
+        // Editor tabs and Agent Manager have no sidebar edge signal. Keep their rail on the physical right in RTL too.
         side={vscode.sidebarSide() ?? "right"}
         entries={entries}
         items={items}

packages/kilo-vscode/webview-ui/src/components/chat/PromptRail.tsx

@@ -94,7 +94,7 @@ export function PromptRail(props: PromptRailProps) {
     const center = rect.top + rect.height / 2 - height / 2
     setAnchor({
       top: max < min ? min : Math.min(Math.max(center, min), max),
-      edge: props.side === "right" ? window.innerWidth - rect.left + GAP : rect.right + GAP,
+      edge: (props.side === "right" ? window.innerWidth - rect.left : rect.right) + GAP,
       height: limit,
     })
   }