feat: remove domains whose zones vanished at the provider on import

internal/api/tenant_handlers.go

@@ -130,19 +130,26 @@ func (a *API) handleImportZones(w http.ResponseWriter, r *http.Request) {
 		writeErr(w, http.StatusInternalServerError, "internal error")
 		return
 	}
-	// Imported atomically: either every zone becomes a domain or none does,
-	// so a mid-batch provider/DB error never leaves a partial import behind.
-	doms, err := a.Store.ImportDomains(r.Context(), pid, aid, zones)
+	// Imported atomically: either every zone becomes a domain (and vanished
+	// zones' domains are deleted) or none of it happens, so a mid-batch
+	// provider/DB error never leaves a partial sync behind.
+	doms, gone, err := a.Store.ImportDomains(r.Context(), pid, aid, zones)
 	if err != nil {
-		log.Printf("api: import: create domains failed: %v", err)
+		log.Printf("api: import: sync domains failed: %v", err)
 		writeErr(w, http.StatusInternalServerError, "internal error")
 		return
 	}
-	created := make([]domainResponse, 0, len(doms))
-	for _, d := range doms {
-		created = append(created, toDomainResponse(d))
+	resp := importResponse{
+		Created: make([]domainResponse, 0, len(doms)),
+		Removed: make([]domainResponse, 0, len(gone)),
 	}
-	writeJSON(w, http.StatusCreated, created)
+	for _, d := range doms {
+		resp.Created = append(resp.Created, toDomainResponse(d))
+	}
+	for _, d := range gone {
+		resp.Removed = append(resp.Removed, toDomainResponse(d))
+	}
+	writeJSON(w, http.StatusCreated, resp)
 }
 
 // --- templates ---