Migrate logicsrc-web from Vite SPA to Next.js 16 App Router

Replaces the Vite single-page app + custom Node server.js with a Next.js
16.2.6 App Router app.

- proxy.ts (src/proxy.ts): www.logicsrc.com -> logicsrc.com 301 over https,
  preserving path + query (the original request, now via Next 16 Proxy).
- One SSR page via an optional catch-all ([[...slug]]) that renders the same
  marketing/spec page for each known top-level route (/docs, /blog, /openspec,
  ...) and 404s unknown paths, preserving existing canonical URLs. Markup is a
  faithful server-rendered port of the old main.ts (SEO upgrade over the prior
  client render); interactivity (hire-us form, CoinPay button, section scroll)
  moves to a client component.
- API routes ported to app/api/**: hire-us coinpay-checkout + project-request,
  oauth/coinpay start/callback/session, webhooks/coinpay. Shared logic in
  src/lib/coinpay.ts (eligibility, payment-rail selection, webhook verify,
  HMAC session sign/verify, cookies).
- commandboard-api (/health + /api/boards|tasks|plugins/*) is no longer mounted
  in-process; next.config.ts proxies those paths to COMMANDBOARD_API_URL via
  afterFiles rewrites (our own /api routes match first).
- Build/start switch to next build / next start. Contract tests rewritten to
  exercise proxy.ts, the route handlers, and pure helpers directly (21 passing);
  Playwright webServer updated.

Deployment (Railway): set COMMANDBOARD_API_URL to the commandboard-api service
URL and run it as its own service; root start now runs next start.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

apps/logicsrc-web/src/app/[[...slug]]/page.tsx

@@ -0,0 +1,41 @@
+import { notFound } from "next/navigation";
+import type { ReactNode } from "react";
+import { renderPageMarkup } from "@/lib/page-markup";
+import { HomeInteractivity } from "@/components/home-interactivity";
+
+// The legacy SPA served the same single page for every top-level path and just
+// scrolled to the matching section. We preserve those URLs (they are canonical
+// in sitemap.xml) by rendering the same page for each known route and 404ing
+// anything else.
+const KNOWN_ROUTES = new Set([
+  "docs",
+  "blog",
+  "openspec",
+  "credential-sharing",
+  "hire-us",
+  "about",
+  "terms",
+  "privacy",
+  "agent-swarm",
+  "agentbyte"
+]);
+
+export default async function Page({
+  params
+}: {
+  params: Promise<{ slug?: string[] }>;
+}): Promise<ReactNode> {
+  const { slug } = await params;
+  if (slug && slug.length > 0) {
+    if (slug.length > 1 || !KNOWN_ROUTES.has(slug[0])) {
+      notFound();
+    }
+  }
+
+  return (
+    <>
+      <div id="app" dangerouslySetInnerHTML={{ __html: renderPageMarkup() }} />
+      <HomeInteractivity />
+    </>
+  );
+}