Add temporary PDF preview links via public token TTL

- Schema: add publicTokenExpiresAt to invoices table
- invoices.generatePublicToken: accepts optional ttlHours param; sets
  expiry timestamp when provided
- invoices.getByPublicToken: returns 403 if token is expired
- New route GET /api/i/[token]/pdf: streams the invoice PDF publicly,
  returns 410 Gone if expired; excluded from auth middleware
- MCP invoices_generate_public_token: exposes ttlHours, returns both
  webUrl (/i/{token}) and pdfUrl (/api/i/{token}/pdf)

https://claude.ai/code/session_014126WHVRT8mftmqkU6dajG

src/app/api/i/[token]/pdf/route.ts

@@ -0,0 +1,54 @@
+import { NextResponse } from "next/server";
+import { eq } from "drizzle-orm";
+import { db } from "~/server/db";
+import { invoices, platformSettings } from "~/server/db/schema";
+import { generateInvoicePDFBlob } from "~/lib/pdf-export";
+
+export const runtime = "nodejs";
+
+export async function GET(
+  _request: Request,
+  { params }: { params: Promise<{ token: string }> },
+) {
+  const { token } = await params;
+
+  const invoice = await db.query.invoices.findFirst({
+    where: eq(invoices.publicToken, token),
+    with: {
+      client: true,
+      business: true,
+      items: { orderBy: (i, { asc }) => [asc(i.position)] },
+    },
+  });
+
+  if (!invoice) {
+    return NextResponse.json({ error: "Not found" }, { status: 404 });
+  }
+
+  if (invoice.publicTokenExpiresAt && new Date(invoice.publicTokenExpiresAt) < new Date()) {
+    return NextResponse.json({ error: "This link has expired" }, { status: 410 });
+  }
+
+  const settings = await db.query.platformSettings.findFirst({
+    where: eq(platformSettings.id, "global"),
+  });
+
+  const pdfBlob = await generateInvoicePDFBlob(invoice, {
+    pdfTemplate: settings?.pdfTemplate as "classic" | "minimal" | undefined,
+    pdfAccentColor: settings?.pdfAccentColor,
+    pdfFooterText: settings?.pdfFooterText,
+    pdfShowLogo: settings?.pdfShowLogo,
+    pdfShowPageNumbers: settings?.pdfShowPageNumbers,
+  });
+
+  const buffer = await pdfBlob.arrayBuffer();
+  const filename = `invoice-${invoice.invoiceNumber}.pdf`;
+
+  return new Response(buffer, {
+    headers: {
+      "Content-Type": "application/pdf",
+      "Content-Disposition": `inline; filename="${filename}"`,
+      "Cache-Control": "private, no-store",
+    },
+  });
+}