fix(web): add Shift+Enter keyboard shortcut to send messages (#209)

On iPadOS with a hardware keyboard, `isTouch` is true (via pointer:coarse)
so submitOnEnter is disabled and there's no keyboard-based way to send.

Add Shift+Enter as a send shortcut that works on all platforms without
changing existing behavior — desktop Enter-to-send is preserved.

Closes #175

via [HAPI](https://hapi.run)

Co-authored-by: HAPI <noreply@hapi.run>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

web/src/components/AssistantChat/HappyComposer.tsx

@@ -258,6 +258,15 @@ export function HappyComposer(props: {
             return
         }
 
+        // Shift+Enter sends the message (works on all platforms including iPadOS with keyboard)
+        if (key === 'Enter' && e.shiftKey) {
+            e.preventDefault()
+            if (!canSend) return
+            api.composer().send()
+            setShowContinueHint(false)
+            return
+        }
+
         if (suggestions.length > 0) {
             if (key === 'ArrowUp') {
                 e.preventDefault()
@@ -308,6 +317,8 @@ export function HappyComposer(props: {
         onPermissionModeChange,
         permissionMode,
         permissionModes,
+        canSend,
+        api,
         haptic
     ])