fix: keep local file picker mounted during composer swaps

Moves the hidden file input out of the attachment controls so it stays mounted.
Prevents file selections from being lost when the composer variant changes.
Restores reliable local attachment uploads after opening the OS picker.

packages/ui/src/components/chat/ChatInput.tsx

@@ -527,8 +527,6 @@ type ComposerAttachmentControlsProps = {
     isVSCode: boolean;
     footerIconButtonClass: string;
     iconSizeClass: string;
-    fileInputRef: React.RefObject<HTMLInputElement | null>;
-    handleLocalFileSelect: (event: React.ChangeEvent<HTMLInputElement>) => void | Promise<void>;
     handlePickLocalFiles: () => void;
     openIssuePicker: () => void;
     openPrPicker: () => void;
@@ -544,8 +542,6 @@ const ComposerAttachmentControls = React.memo(function ComposerAttachmentControl
         isVSCode,
         footerIconButtonClass,
         iconSizeClass,
-        fileInputRef,
-        handleLocalFileSelect,
         handlePickLocalFiles,
         openIssuePicker,
         openPrPicker,
@@ -554,15 +550,6 @@ const ComposerAttachmentControls = React.memo(function ComposerAttachmentControl
 
     return (
         <div className="flex items-center gap-x-1.5">
-            <input
-                ref={fileInputRef}
-                type="file"
-                multiple
-                className="hidden"
-                onChange={handleLocalFileSelect}
-                accept="*/*"
-            />
-
             <div className="relative inline-flex">
                 {props.onOpenMobileSheet ? (
                     <button
@@ -4907,8 +4894,6 @@ const ChatInputComponent: React.FC<ChatInputProps> = ({ onOpenSettings, scrollTo
                                 isVSCode={isVSCode}
                                 footerIconButtonClass={footerIconButtonClass}
                                 iconSizeClass={iconSizeClass}
-                                fileInputRef={fileInputRef}
-                                handleLocalFileSelect={handleLocalFileSelect}
                                 handlePickLocalFiles={handlePickLocalFiles}
                                 openIssuePicker={openIssuePicker}
                                 openPrPicker={openPrPicker}
@@ -5285,8 +5270,6 @@ const ChatInputComponent: React.FC<ChatInputProps> = ({ onOpenSettings, scrollTo
                                             isVSCode={isVSCode}
                                             footerIconButtonClass={footerIconButtonClass}
                                             iconSizeClass={iconSizeClass}
-                                            fileInputRef={fileInputRef}
-                                            handleLocalFileSelect={handleLocalFileSelect}
                                             handlePickLocalFiles={handlePickLocalFiles}
                                             openIssuePicker={openIssuePicker}
                                             openPrPicker={openPrPicker}
@@ -5350,8 +5333,6 @@ const ChatInputComponent: React.FC<ChatInputProps> = ({ onOpenSettings, scrollTo
                                         isVSCode={isVSCode}
                                         footerIconButtonClass={footerIconButtonClass}
                                         iconSizeClass={iconSizeClass}
-                                        fileInputRef={fileInputRef}
-                                        handleLocalFileSelect={handleLocalFileSelect}
                                         handlePickLocalFiles={handlePickLocalFiles}
                                         openIssuePicker={openIssuePicker}
                                         openPrPicker={openPrPicker}
@@ -5480,6 +5461,21 @@ const ChatInputComponent: React.FC<ChatInputProps> = ({ onOpenSettings, scrollTo
             isMobile={isMobile}
         />
 
+        {/* Single always-mounted picker input. It must NOT live inside
+            ComposerAttachmentControls: that component mounts once per composer
+            variant (pill / expanded footer), so a shared ref got nulled when a
+            variant unmounted, and a variant swap while the OS file picker was
+            open detached the clicked input — its change event was silently
+            lost and the picked files never attached. */}
+        <input
+            ref={fileInputRef}
+            type="file"
+            multiple
+            className="hidden"
+            onChange={handleLocalFileSelect}
+            accept="*/*"
+        />
+
         {/* Mobile attachment sheet: replaces the dropdown (which stole focus and
             dismissed the keyboard) and leaves room for more actions later. */}
         {isMobile ? (