feat: auditoría SEO real con histórico y avisos

Crawl técnico (HTTPS/robots/sitemap/on-page) + tabla seo_audits; UI con nota, checks y alertas.

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

sql/seo_audits.sql

@@ -0,0 +1,31 @@
+-- SEO site audit history (technical checks + score)
+-- Idempotent.
+
+create table if not exists public.seo_audits (
+  id uuid primary key default gen_random_uuid(),
+  tenant_id uuid not null references public.tenants(id) on delete cascade,
+  site_url text not null,
+  score numeric not null default 0,
+  grade text not null default 'F',
+  warning_count integer not null default 0,
+  critical_count integer not null default 0,
+  checks jsonb not null default '[]'::jsonb,
+  summary text,
+  created_at timestamptz not null default now()
+);
+
+create index if not exists seo_audits_tenant_created_idx
+  on public.seo_audits (tenant_id, created_at desc);
+
+alter table public.seo_audits enable row level security;
+
+drop policy if exists seo_audits_tenant_select on public.seo_audits;
+create policy seo_audits_tenant_select on public.seo_audits
+  for select using (
+    tenant_id::text = coalesce(
+      auth.jwt() -> 'app_metadata' ->> 'tenant_id',
+      auth.jwt() -> 'user_metadata' ->> 'tenant_id'
+    )
+  );
+
+-- Agency writes via service role (bypasses RLS).