New adapter: Panxo

Add documentation for Panxo bid adapter with Prebid Server support.

Owner: Panxo Stacks, Inc.

Author: Joan Faura

dev-docs/bidders/panxo.md

@@ -15,7 +15,8 @@ media_types: banner
 safeframes_ok: true
 bidder_supports_deals: true
 pbjs: true
-pbs: false
+pbs: true
+pbs_app_supported: false
 prebid_member: true
 multiformat_supported: will-not-bid
 ortb_blocking_supported: false
@@ -106,6 +107,22 @@ pbjs.setConfig({
 });
 ```
 
+### Prebid Server
+
+Panxo supports server-side bidding through Prebid Server. The Panxo RTD module must still be configured in Prebid.js on the client side, as it detects AI-referred traffic and injects the user identifier that Prebid Server forwards to the Panxo endpoint.
+
+#### Prebid Server Configuration
+
+```yaml
+adapters:
+  panxo:
+    endpoint: "https://panxo-sys.com/openrtb/2.5/bid"
+```
+
+#### Client-Side Requirements for PBS
+
+When using Prebid Server, the Panxo RTD module runs on the client and enriches the OpenRTB request with `device.ext.panxo`, which PBS forwards to the Panxo adapter. No additional client-side configuration is required beyond the standard RTD module setup shown above.
+
 ### Additional Notes
 
 - **Net Revenue**: Bids are returned as net revenue.