Allow direct local file upload (PDF/Image/Video) for WhatsApp Media Header templates instead of requiring a public URL

[ldaniel-jmz]

Is your feature or enhancement related to a problem? Please describe.

Currently, when sending a WhatsApp Cloud API message template that includes a media header (DOCUMENT, IMAGE, or VIDEO), the Chatwoot UI (TemplateParser.vue) only renders a plain text input requiring the agent to manually paste an external, publicly accessible HTTPS URL (media_url).

In real-world support and sales workflows, human agents have files (such as invoices, quotes in PDF, or product images) stored locally on their computers. Forcing agents to upload a local PDF/image to an external hosting service or public S3 bucket just to copy and paste a public link into the template modal creates significant operational friction and slows down response times.

Describe the solution you'd like

Allow agents to upload or drag-and-drop a local file (<input type="file">) directly inside the WhatsApp Template modal when the selected template has a HEADER component with format DOCUMENT, IMAGE, or VIDEO (while optionally keeping the URL input as a fallback/tab).

From a technical standpoint, this could be handled in one of two ways:

1. Via ActiveStorage / Direct Upload: Upload the file using Chatwoot's existing ActiveStorage pipeline (similar to standard conversation attachments), generate a publicly accessible/signed URL, and inject it into processedParams.header.media_url (and automatically populate media_name from file.name for DOCUMENT headers).

2. Via Meta's /media Endpoint (Recommended for private/self-hosted instances): Upload the binary directly to WhatsApp Cloud API's /vXX.0/{phone_number_id}/media endpoint, retrieve the media_id, and send the template header parameter using { "type": "document", "document": { "id": "<MEDIA_ID>", "filename": "..." } } instead of link. This avoids issues where self-hosted Chatwoot instances use private storage buckets not reachable by Meta's servers.

Describe alternatives you've considered

• Asking agents to upload the file to an external cloud drive / S3 bucket first and paste the link (error-prone and poor UX for non-technical agents).

• Sending a text-only template first, waiting for the customer to reply to open the 24-hour window, and then attaching the local PDF as a regular message (adds unnecessary steps when the business needs to deliver the document immediately in the first outbound message).

Additional context

• Frontend component impacted: app/javascript/dashboard/components/widgets/conversation/WhatsappTemplates/TemplateParser.vue

• Backend service impacted: app/services/whatsapp/providers/whatsapp_cloud_service.rb

[ldaniel-jmz]

Tracked in Issue #16256