Even further app fixes (#9617)

- Allow dragging zoom pane with middle click
- Prevent selection of canvasOnly widgets
- These widgets would not display in app mode, so allow selection would
only cause confusion.
- Support displaying the error dialogue in app mode
- Add a somewhat involved mobile app mode error indication system
<img width="300" alt="image"
src="https://github.com/user-attachments/assets/d8793bbd-fff5-4b2a-a316-6ff154bae2c4"
/> <img width="300" alt="image"
src="https://github.com/user-attachments/assets/cb88b0f6-f7e5-409e-ae43-f1348f946b19"
/>

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9617-Even-further-app-fixes-31d6d73d365081c891dfdfe3477cfd61)
by [Unito](https://www.unito.io)

src/components/common/Dialogue.vue

@@ -0,0 +1,51 @@
+<script setup lang="ts">
+import {
+  DialogClose,
+  DialogContent,
+  DialogOverlay,
+  DialogPortal,
+  DialogRoot,
+  DialogTitle,
+  DialogTrigger
+} from 'reka-ui'
+import { useI18n } from 'vue-i18n'
+
+import Button from '@/components/ui/button/Button.vue'
+
+defineProps<{ title?: string; to?: string | HTMLElement }>()
+
+const { t } = useI18n()
+</script>
+<template>
+  <DialogRoot v-slot="{ close }">
+    <DialogTrigger as-child>
+      <slot name="button" />
+    </DialogTrigger>
+    <DialogPortal :to>
+      <DialogOverlay
+        class="data-[state=open]:animate-overlayShow fixed inset-0 z-30 bg-black/70"
+      />
+      <DialogContent
+        v-bind="$attrs"
+        class="data-[state=open]:animate-contentShow fixed top-[50%] left-[50%] z-1700 max-h-[85vh] w-[90vw] max-w-[450px] translate-x-[-50%] translate-y-[-50%] rounded-2xl border border-border-subtle bg-base-background p-2 shadow-sm"
+      >
+        <div
+          v-if="title"
+          class="flex w-full items-center justify-between border-b border-border-subtle px-4"
+        >
+          <DialogTitle class="text-sm">{{ title }}</DialogTitle>
+          <DialogClose as-child>
+            <Button
+              :aria-label="t('g.close')"
+              size="icon"
+              variant="muted-textonly"
+            >
+              <i class="icon-[lucide--x]" />
+            </Button>
+          </DialogClose>
+        </div>
+        <slot :close />
+      </DialogContent>
+    </DialogPortal>
+  </DialogRoot>
+</template>