fix(ui): reduce prompt expanded height on mobile

Use the existing instance shell layout mode to cap expanded prompt rows to 10 on phone/tablet while keeping 15 on desktop.

packages/ui/src/components/instance/instance-shell2.tsx

@@ -124,6 +124,7 @@ const InstanceShell2: Component<InstanceShellProps> = (props) => {
 
   const isPhoneLayout = createMemo(() => layoutMode() === "phone")
   const mobileFullscreen = createMemo(() => props.mobileFullscreenMode && isPhoneLayout())
+  const compactPromptLayout = createMemo(() => layoutMode() !== "desktop")
   const leftPinningSupported = createMemo(() => layoutMode() !== "phone")
   const rightPinningSupported = createMemo(() => layoutMode() !== "phone")
 
@@ -824,6 +825,7 @@ const InstanceShell2: Component<InstanceShellProps> = (props) => {
                           instanceFolder={props.instance.folder}
                           escapeInDebounce={props.escapeInDebounce}
                           isPhoneLayout={isPhoneLayout()}
+                          compactPromptLayout={compactPromptLayout()}
                           showSidebarToggle={showEmbeddedSidebarToggle()}
                           onSidebarToggle={() => setLeftOpen(true)}
                           forceCompactStatusLayout={showEmbeddedSidebarToggle()}

packages/ui/src/components/prompt-input.tsx

@@ -455,7 +455,7 @@ export default function PromptInput(props: PromptInputProps) {
                 onFocus={() => setIsFocused(true)}
                 onBlur={() => setIsFocused(false)}
                 disabled={props.disabled}
-                rows={expandState() === "expanded" ? 15 : 3}
+                rows={expandState() === "expanded" ? (props.compactLayout ? 10 : 15) : 3}
                 spellcheck={false}
                 autocorrect="off"
                 autoCapitalize="off"

packages/ui/src/components/prompt-input/types.ts

@@ -20,6 +20,9 @@ export interface PromptInputProps {
 
   // Used to scope global "type-to-focus" behavior.
   isActive?: boolean
+
+  // Phone/tablet layouts should keep the expanded prompt more compact.
+  compactLayout?: boolean
   onSend: (prompt: string, attachments: Attachment[]) => Promise<void>
   onRunShell?: (command: string) => Promise<void>
   disabled?: boolean

packages/ui/src/components/session/session-view.tsx

@@ -29,6 +29,7 @@ interface SessionViewProps {
   instanceFolder: string
   escapeInDebounce: boolean
   isPhoneLayout?: boolean
+  compactPromptLayout?: boolean
   showSidebarToggle?: boolean
   onSidebarToggle?: () => void
   forceCompactStatusLayout?: boolean
@@ -322,6 +323,7 @@ export const SessionView: Component<SessionViewProps> = (props) => {
                 instanceFolder={props.instanceFolder}
                 sessionId={activeSession.id}
                 isActive={props.isActive}
+                compactLayout={props.compactPromptLayout}
                 onSend={handleSendMessage}
                 onRunShell={handleRunShell}
                 escapeInDebounce={props.escapeInDebounce}