Add "Powered by Zerocost" Ad Watermark (Click Message to View Spec)

SPEC: Every ad rendered through the Zerocost SDK includes a small watermark consisting of the Zerocost favicon positioned to the left of the “X” close button across all ad formats. The favicon acts as a clickable element that opens the Zerocost landing page in a new tab (BASE URL) so audiences encountering the ad inside software products can discover how Zerocost enables that application to monetize without charging users. When users hover over the favicon, a tooltip appears displaying the text “Powered by Zerocost.” Clicking the favicon navigates directly to the landing page. The watermark is enabled by default for all publishers integrating Zerocost to support early network visibility. Once an application reaches 100,000 cumulative ad impressions, the publisher becomes eligible to disable the watermark. At that point, a toggle labeled “Remove ‘Powered by Zerocost’ watermark” becomes available in the Startup Dashboard → Ad Display tab, allowing the developer to remove or keep the watermark as long as the account is in good standing and the Ads product remains active.