feat: optimize changes refresh and simplify input bar

- Reduce refresh debounce to 150ms for faster updates
- Keep smart loading to prevent UI flicker
- Remove placeholder text from input bar for cleaner UI

Author: bohutang

packages/ui/src/components/layout/InputBar.tsx

@@ -1105,14 +1105,6 @@ export const InputBar: React.FC<InputBarProps> = React.memo(({
                   color="var(--st-text)"
                   opacity={isFocused ? 0.7 : 0.3}
                 />
-                {isEmpty && !isRunning && (
-                  <div
-                    className="absolute top-0 left-0 text-[13px] pointer-events-none"
-                    style={{ color: 'var(--st-text-faint)', opacity: 0.6 }}
-                  >
-                    {placeholder}
-                  </div>
-                )}
               </div>
 
               <div className="flex items-center gap-2 mt-2 text-[12px]">

packages/ui/src/components/layout/useRightPanelData.ts

@@ -241,7 +241,7 @@ export function useRightPanelData(sessionId: string | undefined): RightPanelData
     refreshTimerRef.current = window.setTimeout(() => {
       refreshTimerRef.current = null;
       refreshRef.current();
-    }, 500); // Increased debounce to reduce flicker
+    }, 150); // Fast refresh with smart loading to avoid UI flicker
   }, []); // No dependencies - scheduleRefresh identity is now stable
 
   useEffect(() => {