Add in-app editorial calendar creator with month zoom and preview.

Agency can pick a month, generate a brand/seasonality preview, and add/edit/delete pieces with the same fields as the creative pipeline, optionally syncing drafts there.

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

src/app/api/calendar/preview/route.ts

@@ -0,0 +1,73 @@
+/**
+ * POST { month: 'YYYY-MM' } → editorial preview for active tenant.
+ */
+import { NextRequest, NextResponse } from 'next/server';
+import { createClient } from '@/lib/supabase/server';
+import { resolveActiveTenant, restGet } from '@/lib/tenant-context';
+import { isAgencyRole, userRole } from '@/lib/agency';
+import { asPlanObject } from '@/lib/calendar-documents';
+import { generateMonthPreview } from '@/lib/calendar-generate';
+import type { RrssMonthPlan } from '@/components/RrssMonthView';
+
+export const dynamic = 'force-dynamic';
+export const maxDuration = 60;
+
+export async function POST(req: NextRequest) {
+  const supabase = await createClient();
+  const {
+    data: { user },
+  } = await supabase.auth.getUser();
+  if (!user) {
+    return NextResponse.json({ error: 'Unauthorized' }, { status: 401 });
+  }
+  if (!isAgencyRole(userRole(user))) {
+    return NextResponse.json({ error: 'Solo agencia' }, { status: 403 });
+  }
+  const ctx = await resolveActiveTenant(user);
+  if (!ctx.tenantId || ctx.portfolioWide) {
+    return NextResponse.json(
+      { error: 'Selecciona un cliente en Contexto.' },
+      { status: 400 }
+    );
+  }
+
+  const body = (await req.json().catch(() => ({}))) as { month?: string };
+  const month = String(body.month || '').slice(0, 7);
+  if (!/^\d{4}-\d{2}$/.test(month)) {
+    return NextResponse.json({ error: 'month YYYY-MM requerido' }, { status: 400 });
+  }
+
+  let slug = 'cliente';
+  const t = await restGet<{ slug?: string }[]>(
+    `/rest/v1/tenants?id=eq.${encodeURIComponent(ctx.tenantId)}&select=slug`
+  );
+  slug = t.data?.[0]?.slug || ctx.label.toLowerCase().replace(/\s+/g, '-');
+
+  const docs = await restGet<{ content?: unknown }[]>(
+    `/rest/v1/documents?tenant_id=eq.${encodeURIComponent(
+      ctx.tenantId
+    )}&type=eq.calendar&select=content&order=created_at.desc&limit=24`
+  );
+  const history: RrssMonthPlan[] = [];
+  for (const d of docs.data || []) {
+    const plan = asPlanObject(d.content) as RrssMonthPlan | null;
+    if (plan?.month && plan.month !== month && Array.isArray(plan.pieces)) {
+      history.push(plan as unknown as RrssMonthPlan);
+    }
+  }
+
+  const result = await generateMonthPreview({
+    ym: month,
+    slug,
+    label: ctx.label,
+    history,
+  });
+
+  return NextResponse.json({
+    ok: true,
+    plan: result.plan,
+    rationale: result.rationale,
+    source: result.source,
+    brand: slug,
+  });
+}