Remove dead mobileComposerExpandFrameRef and cancelPendingExpandFocus

The ref was never assigned a non-null value after the refactoring to
synchronous focus. This made cancelPendingExpandFocus always a no-op
and the cleanup effect for this ref dead code. Remove the ref, callback,
interface member, and test assertion.

Author: cursoragent

apps/web/src/components/chat/ChatComposer.tsx

@@ -813,7 +813,6 @@ export const ChatComposer = memo(
     const composerMenuItemsRef = useRef<ComposerCommandItem[]>([]);
     const activeComposerMenuItemRef = useRef<ComposerCommandItem | null>(null);
     const composerBlurFrameRef = useRef<number | null>(null);
-    const mobileComposerExpandFrameRef = useRef<number | null>(null);
     const mobileComposerExpandReleaseFrameRef = useRef<number | null>(null);
     const mobileComposerExpandInFlightRef = useRef(false);
     const dragDepthRef = useRef(0);
@@ -1636,12 +1635,6 @@ export const ChatComposer = memo(
             composerBlurFrameRef.current = null;
           }
         },
-        cancelPendingExpandFocus: () => {
-          if (mobileComposerExpandFrameRef.current !== null) {
-            window.cancelAnimationFrame(mobileComposerExpandFrameRef.current);
-            mobileComposerExpandFrameRef.current = null;
-          }
-        },
         cancelPendingRelease: () => {
           if (mobileComposerExpandReleaseFrameRef.current !== null) {
             window.cancelAnimationFrame(mobileComposerExpandReleaseFrameRef.current);
@@ -1844,9 +1837,6 @@ export const ChatComposer = memo(
         if (composerBlurFrameRef.current !== null) {
           window.cancelAnimationFrame(composerBlurFrameRef.current);
         }
-        if (mobileComposerExpandFrameRef.current !== null) {
-          window.cancelAnimationFrame(mobileComposerExpandFrameRef.current);
-        }
         if (mobileComposerExpandReleaseFrameRef.current !== null) {
           window.cancelAnimationFrame(mobileComposerExpandReleaseFrameRef.current);
         }

apps/web/src/components/chat/mobileComposerFocus.test.ts

@@ -7,7 +7,6 @@ describe("expandMobileComposerForKeyboard", () => {
 
     expandMobileComposerForKeyboard({
       cancelPendingBlur: vi.fn(() => calls.push("cancel-blur")),
-      cancelPendingExpandFocus: vi.fn(() => calls.push("cancel-expand-focus")),
       cancelPendingRelease: vi.fn(() => calls.push("cancel-release")),
       setExpandInFlight: vi.fn((inFlight) => calls.push(`in-flight:${inFlight}`)),
       commitExpandedState: vi.fn(() => calls.push("commit-expanded")),
@@ -17,7 +16,6 @@ describe("expandMobileComposerForKeyboard", () => {
 
     expect(calls).toEqual([
       "cancel-blur",
-      "cancel-expand-focus",
       "cancel-release",
       "in-flight:true",
       "commit-expanded",

apps/web/src/components/chat/mobileComposerFocus.ts

@@ -1,6 +1,5 @@
 export interface MobileComposerExpandOptions {
   cancelPendingBlur: () => void;
-  cancelPendingExpandFocus: () => void;
   cancelPendingRelease: () => void;
   setExpandInFlight: (inFlight: boolean) => void;
   commitExpandedState: () => void;
@@ -10,7 +9,6 @@ export interface MobileComposerExpandOptions {
 
 export function expandMobileComposerForKeyboard(options: MobileComposerExpandOptions) {
   options.cancelPendingBlur();
-  options.cancelPendingExpandFocus();
   options.cancelPendingRelease();
   options.setExpandInFlight(true);
   options.commitExpandedState();