feat: metrics dashboard with WoW/MoM/YoY and creatives pipeline

Rebuild KPIs as a real dashboard (period deltas, tenant zoom), clarify
objetivos/calendario/activos sources, and turn creatives into a status
pipeline with delete.

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

sql/creatives_delete_policy.sql

@@ -0,0 +1,11 @@
+-- Allow tenant-scoped delete on creatives (clients); agency uses service role.
+alter table public.creatives enable row level security;
+
+drop policy if exists creatives_tenant_delete on public.creatives;
+create policy creatives_tenant_delete on public.creatives
+  for delete using (
+    tenant_id::text = coalesce(
+      auth.jwt() -> 'app_metadata' ->> 'tenant_id',
+      auth.jwt() -> 'user_metadata' ->> 'tenant_id'
+    )
+  );