Add banner ID to probo_consent cookie

Include a `bid` field in the consent cookie so it explicitly
identifies which cookie banner it belongs to, making validation
direct instead of relying on the visitor ID as an implicit
discriminator. Existing cookies without `bid` self-heal on the
next load by falling through to the API fetch.

Signed-off-by: Émile Ré <emile@getprobo.com>

pkg/server/api/cookiebanner/v1/handler.go

@@ -122,6 +122,7 @@ type (
 		Version     int                          `json:"version"`
 		Action      coredata.CookieConsentAction `json:"action"`
 		ConsentData json.RawMessage              `json:"consent_data"`
+		SdkVersion  string                       `json:"sdk_version"`
 	}
 
 	postConsentResponse struct {
@@ -155,6 +156,7 @@ func (h *Handler) handlePostConsent(w http.ResponseWriter, r *http.Request) {
 		UserAgent:   &ua,
 		ConsentData: body.ConsentData,
 		Action:      body.Action,
+		SdkVersion:  body.SdkVersion,
 	}
 
 	record, err := h.cookieBannerSvc.RecordConsent(r.Context(), bannerID, req)