fix: mostrar Google Ads desde ad_daily cuando kpi_weekly está vacío

kpi_weekly es una MV de solo lectura sin canales paid; canal/seguimiento
ahora hacen fallback a ad_daily. Bump Google Ads API a v21 en sync.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/lib/ads-sync.ts

@@ -4,7 +4,7 @@ import { serviceHeaders, supabaseUrl } from '@/lib/agency';
 import { resolveMetaAccessToken } from '@/lib/ads-discovery';
 
 const META_GRAPH = 'https://graph.facebook.com/v21.0';
-const GADS_API = 'https://googleads.googleapis.com/v18';
+const GADS_API = 'https://googleads.googleapis.com/v21';
 
 export type SyncTenantResult = {
   tenantId: string;
@@ -285,14 +285,16 @@ async function fetchGoogleCampaignDaily(
     const date = row.segments?.date;
     if (!date) continue;
     const spend = Math.round((n(row.metrics?.costMicros) / 1_000_000) * 100) / 100;
+    const campaignId = row.campaign?.id ? String(row.campaign.id) : null;
     out.push({
       tenant_id: tenantId,
       date,
       platform: 'google',
-      campaign_id: row.campaign?.id ? String(row.campaign.id) : null,
+      campaign_id: campaignId,
       campaign_name: row.campaign?.name || null,
-      ad_id: null,
-      ad_name: null,
+      // ad_daily.ad_id is NOT NULL — campaign-level rows reuse campaign id
+      ad_id: campaignId || '',
+      ad_name: '',
       impressions: n(row.metrics?.impressions),
       clicks: n(row.metrics?.clicks),
       spend,