Add Alva (alvads) bidder adapter documentation

dev-docs/bidders/alvads.md

@@ -0,0 +1,140 @@
+---
+layout: bidder
+title: Alva
+description: Prebid Alva Bidder Adapter
+pbjs: true
+pbs_app_supported: false
+biddercode: alvads
+media_types: banner, video
+gdpr_supported: true
+usp_supported: true
+coppa_supported: false
+---
+
+# Overview
+
+**Module Name:** alvadsBidAdapter  
+**Module Type:** Bidder  
+**Maintainer:** [[email protected]](mailto:[email protected])
+
+---
+
+# Description
+
+The **Alva Bid Adapter** allows publishers to connect their banner and video inventory with the Alva demand platform.
+
+- **Bidder Code:** `alvads`
+- **Supported Media Types:** `banner`, `video`
+- **Protocols:** OpenRTB 2.5 via `POST` (banner and video)
+- **Dynamic Endpoints:** The adapter uses a default endpoint, but can be overridden via `params.endpoint`.
+
+---
+
+# Test Parameters
+
+### Banner Example
+
+```javascript
+var adUnits = [{
+  code: 'div-banner',
+  mediaTypes: {
+    banner: {
+      sizes: [[300, 250], [320, 100]]
+    }
+  },
+  bids: [{
+    bidder: 'alvads',
+    params: {
+      publisherId: 'pub-123',    // required
+      tagid: 'tag-456',          // required for banner
+      bidfloor: 0.50,            // optional
+      userId: '+59165352182',    // optional
+      endpoint: 'https://custom-endpoint.com/openrtb' // optional, overrides default
+    }
+  }]
+}];
+```
+
+### Video Example
+
+```javascript
+var adUnits = [{
+  code: 'video-ad',
+  mediaTypes: {
+    video: {
+      context: 'instream',
+      playerSize: [[640, 360]]
+    }
+  },
+  bids: [{
+    bidder: 'alvads',
+    params: {
+      publisherId: 'pub-123',     // required
+      bidfloor: 0.5,              // optional
+      userId: '+59165352182',     // optional
+      endpoint: 'https://custom-endpoint.com/video' // optional, overrides default
+    }
+  }]
+}];
+```
+
+---
+
+# Request Information
+
+### Banner / Video
+- **Default Endpoint:**
+  ```
+  https://helios-ads-qa-core.ssidevops.com/decision/openrtb
+  ```
+- **Method:** `POST`
+- **Payload:** OpenRTB 2.5 request containing `site`, `device`, `user`, `regs`, and `imp`.
+- **Dynamic Endpoint:** Can be overridden via `bid.params.endpoint`.
+
+---
+
+# Response Information
+
+### Banner
+The response is standard OpenRTB with `seatbid`.
+
+```json
+{
+  "id": "response-id",
+  "seatbid": [{
+    "bid": [{
+      "impid": "imp-123",
+      "price": 0.50,
+      "adm": "<div>Creative</div>",
+      "crid": "creative-1",
+      "w": 320,
+      "h": 100,
+      "ext": {
+        "vast_url": "http://example.com/vast.xml"
+      },
+      "adomain": ["example.com"]
+    }]
+  }],
+  "cur": "USD"
+}
+```
+
+### Interpretation
+- If `adm` contains `<VAST>`, the adapter sets `mediaType: 'video'` and includes `vastXml` & `vastUrl`.
+- Otherwise, `mediaType: 'banner'` and the ad contains the HTML markup.
+
+---
+
+# Additional Details
+
+- **Defaults:**
+    - `netRevenue = true`
+    - `ttl = 300`
+    - Banner fallback size: `320x100`
+    - Video fallback size: `1280x720`
+
+- **Callbacks:**
+    - `onTimeout` → logs timeout events
+    - `onBidWon` → logs winning bids
+
+---