feat(documents): create-document wizard MVP + service dispatch

Implements createFromWizard and createFromUpload service paths covering
the documenso-template, in-app, and upload pathways. Persists subject
FK, signers, watchers, and the per-document reminder controls
(remindersDisabled / reminderCadenceOverride) introduced in PR1. New
POST /api/v1/documents/wizard route and a functional /documents/new UI
with type/source/template/signers/reminders sections. Drag-handle
reorder, watcher autocomplete picker, and PDF preview defer to the
PR10 polish sweep.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/app/(dashboard)/[portSlug]/documents/new/page.tsx

@@ -1,6 +1,4 @@
-import Link from 'next/link';
-import { Button } from '@/components/ui/button';
-import { PageHeader } from '@/components/shared/page-header';
+import { CreateDocumentWizard } from '@/components/documents/create-document-wizard';
 
 interface PageProps {
   params: Promise<{ portSlug: string }>;
@@ -8,17 +6,5 @@ interface PageProps {
 
 export default async function NewDocumentPage({ params }: PageProps) {
   const { portSlug } = await params;
-  return (
-    <div className="flex flex-col gap-4">
-      <PageHeader
-        title="New document"
-        description="The create-document wizard ships in PR6 of the Phase A rollout."
-        actions={
-          <Button asChild variant="outline">
-            <Link href={`/${portSlug}/documents`}>Back to documents</Link>
-          </Button>
-        }
-      />
-    </div>
-  );
+  return <CreateDocumentWizard portSlug={portSlug} />;
 }

src/app/api/v1/documents/wizard/route.ts

@@ -0,0 +1,24 @@
+import { NextResponse } from 'next/server';
+
+import { withAuth, withPermission } from '@/lib/api/helpers';
+import { parseBody } from '@/lib/api/route-helpers';
+import { errorResponse } from '@/lib/errors';
+import { createFromWizard } from '@/lib/services/documents.service';
+import { createDocumentWizardSchema } from '@/lib/validators/documents';
+
+export const POST = withAuth(
+  withPermission('documents', 'create', async (req, ctx) => {
+    try {
+      const body = await parseBody(req, createDocumentWizardSchema);
+      const doc = await createFromWizard(ctx.portId, body, {
+        userId: ctx.userId,
+        portId: ctx.portId,
+        ipAddress: ctx.ipAddress,
+        userAgent: ctx.userAgent,
+      });
+      return NextResponse.json({ data: doc }, { status: 201 });
+    } catch (error) {
+      return errorResponse(error);
+    }
+  }),
+);