refactor(chat): remove keyboard compatibility layer

src/app/chat/hooks/use-chat-keyboard-diagnostics.ts

@@ -6,7 +6,6 @@ import { BrowserDetector } from "@/utils/browser-detect";
 import { PlatformDetector } from "@/utils/platform-detect";
 
 const CHAT_KEYBOARD_DEBUG_PARAM = "keyboard_debug";
-const CHAT_INPUT_LIFT_VAR = "--chat-input-lift";
 
 interface VirtualKeyboardLike extends EventTarget {
   readonly boundingRect?: Pick<
@@ -41,7 +40,11 @@ export interface ChatKeyboardDebugSnapshot {
   activeElement: string | null;
   activeBottom: number | null;
   activeFocused: boolean;
-  inputLift: string | null;
+  inputBarTop: number | null;
+  inputBarBottom: number | null;
+  appViewportHeight: string | null;
+  appVisibleHeight: string | null;
+  appVisibleOffsetTop: string | null;
   viewportMeta: string | null;
   platform: {
     name: string;
@@ -151,6 +154,8 @@ function createChatKeyboardDebugSnapshot(
       : null;
   const platform = PlatformDetector.getPlatformInfo();
   const browser = BrowserDetector.getBrowserInfo();
+  const rootStyle = document.documentElement.style;
+  const inputBarRect = containerRef.current?.getBoundingClientRect() ?? null;
 
   return {
     event,
@@ -176,8 +181,14 @@ function createChatKeyboardDebugSnapshot(
     activeElement: activeElement?.tagName ?? null,
     activeBottom: activeRect?.bottom ?? null,
     activeFocused: activeElement !== document.body,
-    inputLift:
-      containerRef.current?.style.getPropertyValue(CHAT_INPUT_LIFT_VAR) || null,
+    inputBarTop: inputBarRect?.top ?? null,
+    inputBarBottom: inputBarRect?.bottom ?? null,
+    appViewportHeight:
+      rootStyle.getPropertyValue("--app-viewport-height") || null,
+    appVisibleHeight:
+      rootStyle.getPropertyValue("--app-visible-height") || null,
+    appVisibleOffsetTop:
+      rootStyle.getPropertyValue("--app-visible-offset-top") || null,
     viewportMeta:
       document.querySelector<HTMLMetaElement>('meta[name="viewport"]')
         ?.content ?? null,