feat(ui): enhance resize handling to maintain selected package visibility

Author: donfear

src/interactive-ui.ts

@@ -253,7 +253,7 @@ export class InteractiveUI {
           case 'resize':
             const heightChanged = stateManager.updateTerminalHeight(action.height)
             if (heightChanged) {
-              stateManager.resetForResize()
+              stateManager.resetForResize(filteredStates.length)
             } else {
               // Even if height didn't change, width might have changed
               // Force a full re-render to clear any wrapping issues

src/ui/state/navigation-manager.ts

@@ -156,9 +156,9 @@ export class NavigationManager {
     if (targetVisualIndex < this.state.scrollOffset) {
       this.state.scrollOffset = targetVisualIndex
     }
-    // Scrolling down: scroll down by 1 item (smooth scrolling)
+    // Scrolling down: adjust scroll to keep item visible
     else if (visualIndex >= this.state.scrollOffset + this.maxVisibleItems) {
-      this.state.scrollOffset += 1
+      this.state.scrollOffset = visualIndex - this.maxVisibleItems + 1
     }
 
     // Ensure scrollOffset doesn't go negative or beyond bounds

src/ui/state/state-manager.ts

@@ -272,8 +272,8 @@ export class StateManager {
     this.renderState.forceFullRender = isInitial
   }
 
-  resetForResize(): void {
-    const totalItems = this.renderState.renderableItems.length || this.displayState.maxVisibleItems
+  resetForResize(totalFilteredItems?: number): void {
+    const totalItems = totalFilteredItems || this.renderState.renderableItems.length || this.displayState.maxVisibleItems
     this.navigationManager.resetForResize(totalItems)
     this.renderState.forceFullRender = true
   }