feat: facturación primer pago, fixes SAT/MP, autocompletado RFCs/conceptos

Backend:
- Notificación email al admin cuando llega primer pago aprobado (sin factura auto)
- Endpoints GET /pagos-sin-factura y POST /emitir-factura-pago para admin global
- Fix vinculación org Facturapi Horux 360 (69f23a5a242e0af47a41fa0d)
- Fix webhook MP: validación defensiva de x-signature header
- Fix autocompleto RFCs: eliminado filtro por contribuyenteId
- Fix autocompleto conceptos: eliminado filtro por contribuyenteId
- SAT fixes: anti-bot CSF scraper, request reuse, date range fix, stale job thresholds
- SAT sync request reuse across jobs para evitar agotar cuota diaria
- Typo fix MP_ACCESS_TOKEN en .env
- Trial invitations system backend

Frontend:
- Nueva página /admin/facturas-pendientes con tabla y emisión manual
- Métrica 'Facturas pendientes' en /clientes (clickable)
- Navegación onboarding FIEL/CSD corregida
- Sidebar themes sincronizados
- Fix SAT portal migration scraper (NetIQ)
- Trial invitation acceptance pages

apps/api/prisma/migrations/20260507201624_add_trial_invitations/migration.sql

@@ -0,0 +1,32 @@
+-- DropIndex
+DROP INDEX "subscription_addons_subscription_id_plan_addon_catalogo_id_key";
+
+-- CreateTable
+CREATE TABLE "trial_invitations" (
+    "id" TEXT NOT NULL,
+    "tenant_id" TEXT NOT NULL,
+    "invited_by" TEXT NOT NULL,
+    "plan" TEXT NOT NULL DEFAULT 'business_control',
+    "duration_days" INTEGER NOT NULL,
+    "status" TEXT NOT NULL DEFAULT 'pending',
+    "token" TEXT NOT NULL,
+    "email_sent_to" TEXT,
+    "sent_at" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "expires_at" TIMESTAMP(3) NOT NULL,
+    "accepted_at" TIMESTAMP(3),
+    "created_at" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+
+    CONSTRAINT "trial_invitations_pkey" PRIMARY KEY ("id")
+);
+
+-- CreateIndex
+CREATE UNIQUE INDEX "trial_invitations_token_key" ON "trial_invitations"("token");
+
+-- CreateIndex
+CREATE INDEX "trial_invitations_tenant_id_idx" ON "trial_invitations"("tenant_id");
+
+-- CreateIndex
+CREATE INDEX "trial_invitations_token_idx" ON "trial_invitations"("token");
+
+-- CreateIndex
+CREATE INDEX "trial_invitations_status_idx" ON "trial_invitations"("status");