Preserve DAM public image URL's in email templates (avoid Base64 conversion)

[#1]

**Current behaviour**

When we upload an email template to AJO, the image references are automatically converted to Base64-encoded data URL's. For example:

<img src="data&colon;image/png;base64,...." />

**Problem**

This conversion makes email proofing and quality review difficult:

1. Reviewers cannot quickly validate or swap assets via our DAM links
2. Templates become harder to compare against source creative
3. It adds overhead to our QC workflows and slows down stakeholder review cycles
4. DAM public URL feature has been enabled for approved image assets, but this benefit is lost when URLs are converted to Base64 encoding

**Requested change**

Please add/enable a setting so that AJO "preserves external image URL's" from our DAM and does not auto-convert them to Base64 on upload.

Example of desired behaviour:

<img src="https://<dam-public-domain>/path/to/asset.png" />

**Acceptance criteria (proposed)**

1. When uploading HTML into AJO, `<img>` tags that reference allowed DAM public domains remain unchanged (no Base64 conversion)
2. AJO Preview and Test Send render images from those URL's reliably

**Rationale**

Our content supply chain relies on DAM-hosted, approved assets. Preserving public URL's:

• Streamlines proofing and QC by keeping assets linkable and inspectable
• Reduces manual steps to validate images across journeys and campaigns

[#2]

@Sukrity_Wadhwa This looks like an enhancement request. Can you move this to the ideas section?

[#3]

Sure! Thanks, @SatheeskannaK for highlighting that.