feat: Add rich template preview for WhatsApp & Twilio Templates (#13206)

This PR introduces a comprehensive, display-only template preview system
for both WhatsApp and Twilio templates rendering of all supported
template types.

This lays the foundation for rich template previews across:
- Template selection modals
- Campaign creation flows
- Message composer
- Message screen.

<img width="1818" height="2058" alt="template-preview"
src="https://github.com/user-attachments/assets/9833b28c-f824-4568-8f74-6da09ac61f62"
/>

---------

Co-authored-by: Sivin Varghese <64252451+iamsivin@users.noreply.github.com>
Co-authored-by: iamsivin <iamsivin@gmail.com>
Co-authored-by: Muhsin <12408980+muhsin-k@users.noreply.github.com>

app/javascript/dashboard/components-next/template-preview/TemplatePreviewExamples.story.vue

@@ -0,0 +1,199 @@
+<script setup>
+import TemplatePreview from './TemplatePreview.vue';
+import {
+  whatsAppTemplates,
+  getWhatsAppVariables,
+} from './templates/whatsapp-templates.js';
+import { twilioTemplates } from './templates/twilio-templates.js';
+</script>
+
+<template>
+  <Story
+    title="Components/TemplatePreviewExamples"
+    :layout="{ type: 'grid', width: 400 }"
+  >
+    <Variant title="WA: Event Invitation (Buttons)">
+      <TemplatePreview
+        :template="whatsAppTemplates[0]"
+        :variables="getWhatsAppVariables(whatsAppTemplates[0])"
+        platform="whatsapp"
+      />
+    </Variant>
+
+    <Variant title="WA: Purchase Receipt (Document)">
+      <TemplatePreview
+        :template="whatsAppTemplates[1]"
+        :variables="getWhatsAppVariables(whatsAppTemplates[1])"
+        platform="whatsapp"
+      />
+    </Variant>
+
+    <Variant title="WA: Discount Coupon (Copy Code)">
+      <TemplatePreview
+        :template="whatsAppTemplates[2]"
+        :variables="getWhatsAppVariables(whatsAppTemplates[2])"
+        platform="whatsapp"
+      />
+    </Variant>
+
+    <Variant title="WA: Support Callback (Phone)">
+      <TemplatePreview
+        :template="whatsAppTemplates[3]"
+        :variables="getWhatsAppVariables(whatsAppTemplates[3])"
+        platform="whatsapp"
+      />
+    </Variant>
+
+    <Variant title="WA: Training Video (Video)">
+      <TemplatePreview
+        :template="whatsAppTemplates[4]"
+        :variables="getWhatsAppVariables(whatsAppTemplates[4])"
+        platform="whatsapp"
+      />
+    </Variant>
+
+    <Variant title="WA: Order Confirmation (Image)">
+      <TemplatePreview
+        :template="whatsAppTemplates[5]"
+        :variables="getWhatsAppVariables(whatsAppTemplates[5])"
+        platform="whatsapp"
+      />
+    </Variant>
+
+    <Variant title="WA: Product Launch (Image + Footer)">
+      <TemplatePreview
+        :template="whatsAppTemplates[6]"
+        :variables="getWhatsAppVariables(whatsAppTemplates[6])"
+        platform="whatsapp"
+      />
+    </Variant>
+
+    <Variant title="WA: Technician Visit (Header + Buttons)">
+      <TemplatePreview
+        :template="whatsAppTemplates[7]"
+        :variables="getWhatsAppVariables(whatsAppTemplates[7])"
+        platform="whatsapp"
+      />
+    </Variant>
+
+    <Variant title="WA: Greet (Simple Text)">
+      <TemplatePreview
+        :template="whatsAppTemplates[8]"
+        :variables="getWhatsAppVariables(whatsAppTemplates[8])"
+        platform="whatsapp"
+      />
+    </Variant>
+
+    <Variant title="WA: Hello World (Header + Footer)">
+      <TemplatePreview
+        :template="whatsAppTemplates[9]"
+        :variables="getWhatsAppVariables(whatsAppTemplates[9])"
+        platform="whatsapp"
+      />
+    </Variant>
+
+    <Variant title="WA: Feedback Request (Button)">
+      <TemplatePreview
+        :template="whatsAppTemplates[10]"
+        :variables="getWhatsAppVariables(whatsAppTemplates[10])"
+        platform="whatsapp"
+      />
+    </Variant>
+
+    <Variant title="WA: Address Update (Header)">
+      <TemplatePreview
+        :template="whatsAppTemplates[11]"
+        :variables="getWhatsAppVariables(whatsAppTemplates[11])"
+        platform="whatsapp"
+      />
+    </Variant>
+
+    <Variant title="WA: Delivery Confirmation">
+      <TemplatePreview
+        :template="whatsAppTemplates[12]"
+        :variables="getWhatsAppVariables(whatsAppTemplates[12])"
+        platform="whatsapp"
+      />
+    </Variant>
+
+    <Variant title="Twilio: Shoe Launch (Media)">
+      <TemplatePreview
+        :template="twilioTemplates[0]"
+        :variables="twilioTemplates[0].variables"
+        platform="twilio"
+      />
+    </Variant>
+
+    <Variant title="Twilio: Product Launch Custom Price (Media)">
+      <TemplatePreview
+        :template="twilioTemplates[1]"
+        :variables="twilioTemplates[1].variables"
+        platform="twilio"
+      />
+    </Variant>
+
+    <Variant title="Twilio: Product Launch (Media)">
+      <TemplatePreview
+        :template="twilioTemplates[2]"
+        :variables="twilioTemplates[2].variables"
+        platform="twilio"
+      />
+    </Variant>
+
+    <Variant title="Twilio: Greet (Text)">
+      <TemplatePreview
+        :template="twilioTemplates[3]"
+        :variables="twilioTemplates[3].variables"
+        platform="twilio"
+      />
+    </Variant>
+
+    <Variant title="Twilio: Order Status (Text)">
+      <TemplatePreview
+        :template="twilioTemplates[4]"
+        :variables="twilioTemplates[4].variables"
+        platform="twilio"
+      />
+    </Variant>
+
+    <Variant title="Twilio: Hello World (Text)">
+      <TemplatePreview
+        :template="twilioTemplates[5]"
+        :variables="twilioTemplates[5].variables"
+        platform="twilio"
+      />
+    </Variant>
+
+    <Variant title="Twilio: Welcome Message New (Quick Reply)">
+      <TemplatePreview
+        :template="twilioTemplates[6]"
+        :variables="twilioTemplates[6].variables"
+        platform="twilio"
+      />
+    </Variant>
+
+    <Variant title="Twilio: SaaS WhatsApp Question (Quick Reply)">
+      <TemplatePreview
+        :template="twilioTemplates[7]"
+        :variables="twilioTemplates[7].variables"
+        platform="twilio"
+      />
+    </Variant>
+
+    <Variant title="Twilio: Welcome Message (Quick Reply)">
+      <TemplatePreview
+        :template="twilioTemplates[8]"
+        :variables="twilioTemplates[8].variables"
+        platform="twilio"
+      />
+    </Variant>
+
+    <Variant title="Twilio: Course Fee Reminder (Call to Action)">
+      <TemplatePreview
+        :template="twilioTemplates[9]"
+        :variables="twilioTemplates[9].variables"
+        platform="twilio"
+      />
+    </Variant>
+  </Story>
+</template>