Add optional advertisement block on forum index page

[avandenberghe]

Background

The pbwowext extension currently provides an ACP-configurable advertisement block that displays on the forum index page alongside the Recent Topics listing. This is a narrow (300px width) HTML block where admins can paste ad code.

Since this feature depends on Recent Topics being active and is displayed as part of the index layout, it would be a better fit as a built-in option in the Recent Topics extension itself.

Current implementation (in pbwowext)

• ACP toggle: enable/disable
• ACP textarea: custom HTML content
• Template var ADS_INDEX_CODE passed to index_body.html
• CSS styling for .advertisement and .donate-button classes

Proposal

Add an optional advertisement block setting to Recent Topics:

• ACP toggle to enable/disable the ad block
• ACP textarea for custom HTML content
• Render it alongside the Recent Topics listing on the forum index

This would allow removing the feature from pbwowext, making it available to all Recent Topics users regardless of whether they use PBWoW styles.