New Adapter: Adswag

[westerschmal]

🔧 Type of changes

• new bid adapter

✨ What's the context?

Adds the Adswag bid adapter — our own port of the Go adapter (prebid/prebid-server#4908, opened alongside by us, the adapter maintainers). Adswag is directly-integrated European supply: banner, video and audio; site and app; EU-hosted endpoint https://bid.adswag.ai/prebid/bid; GVL vendor 1417; GPP supported; geoscope EEA.

🧠 Rationale behind the change

Same semantics as the Go adapter: per-imp param validation (publisherId required; invalid imps dropped with a bad-input error, valid ones proceed), imp.ext rewritten to imp.ext.adswag.placement_id, publisher id promoted to site.publisher.id/app.publisher.id, everything else passes through in-band. Response side resolves media type per bid (banner/video/audio), backfills w/h/mtype, defaults currency to EUR, and synthesizes iframe markup only for legacy serve-url-only display bids (current production sends markup in adm). modifying-vast-xml-allowed: false — our ad server owns VAST composition and measurement beacons. Consent-gated usersync redirect on ev.adswag.ai (uid only with vendor-1417 + Purpose-1 consent).

🔎 New Bid Adapter Checklist

• verify email contact works — prebid@adswag.ai (monitored)
• NO fully dynamic hostnames — static endpoint in bidder-config yaml
• geographic host parameters are NOT required
• direct use of HTTP is prohibited - implements Bidder<BidRequest> via the standard HttpRequest/BidderBid types
• if the ORTB is just forwarded to the endpoint, use the generic adapter - not applicable: the adapter rewrites imp.ext, promotes the publisher id, and resolves media types/markup on the response
• cover an adapter configuration with an integration test — AdswagTest (WireMock exchange) + IT fixtures

🧪 Test plan

• AdswagBidderTest: 21/21 (includes a captured-production-response mapping test; fixture tokens synthetic)
• IT AdswagTest: 1/1 (full Spring boot + WireMock)
• BidderParamValidatorTest 25/25 and ApplicationTest 27/27 (config/schema consistency gates, re-run with the adswag yaml registered)
• checkstyle: 0 violations on the added files (JDK 25, Maven 3.9.16)
• Live bidder params for validating bids (verified against production 2026-08-13, €2.50 EUR test bids): { "publisherId": "prebid-test", "placementId": "prebid-test-display" } (display imps must include 300x250; prebid-test-video / prebid-test-audio for video/audio)

🏎 Quality check

• Are your changes following our code style guidelines?
• Are there any breaking changes in your code? — No
• Does your test coverage exceed 90%? — Yes
• Are there any erroneous console logs, debuggers or leftover code in your changes? — No

Docs PR (one bidder page, pbs + pbs_app_supported metadata): prebid/prebid.github.io#6702