feat(web): AEO foundation — robots, JSON-LD, meta, llms.txt, security headers

Implements the high-signal, content-independent fixes flagged across the
multi-engine AEO audit:

- robots.txt (app/robots.ts): allow mainstream + AI crawlers (GPTBot,
  ClaudeBot, PerplexityBot, Google-Extended, …), disallow /api, link sitemap.
- Organization + WebSite JSON-LD on the root layout; BlogPosting JSON-LD on
  /blog/[slug].
- Richer metadata: descriptive default title, Open Graph + Twitter cards,
  canonical, icons, metadataBase.
- Per-route titles/descriptions for catch-all routes (docs, about, hire-us,
  agent-swarm, …) instead of the generic "LogicSRC".
- /llms.txt (llmstxt.org) and /skill.md capability manifest.
- /.well-known/security.txt (RFC 9116).
- Security headers via next.config: HSTS, X-Content-Type-Options,
  X-Frame-Options, Referrer-Policy, Permissions-Policy (CSP intentionally
  deferred to avoid breaking inline/stats/CoinPay scripts).

Verified in a running build: all routes serve correctly and headers are set.

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

apps/logicsrc-web/src/app/llms.txt/route.ts

@@ -0,0 +1,37 @@
+const SITE_URL = (process.env.PUBLIC_URL ?? "https://logicsrc.com").replace(/\/$/, "");
+
+// GET /llms.txt — concise, link-rich orientation for LLM crawlers
+// (https://llmstxt.org spec).
+export function GET(): Response {
+  const body = `# LogicSRC
+
+> Open schemas, primitives, and conventions for coordination between humans, AI agents, plugins, payment systems, and hosted products. LogicSRC defines the shared language; products can implement it without owning the standard. A Profullstack, Inc. open-specification project.
+
+## Core
+
+- [Home](${SITE_URL}/): Overview, standards surface, schemas, CLI, and reference implementations.
+- [Docs](${SITE_URL}/docs): Specification guides and conventions.
+- [OpenSpec](${SITE_URL}/openspec): LogicSRC vs OpenSpec.dev comparison and compatibility mode.
+- [Blog](${SITE_URL}/blog): Project notes and release announcements.
+- [Blog RSS](${SITE_URL}/blog/rss.xml): Machine-readable feed of posts.
+
+## Standards & products
+
+- [AgentSwarm](${SITE_URL}/agent-swarm): Provider-neutral agent orchestration, model routing, and cost controls.
+- [AgentByte](${SITE_URL}/agentbyte): Agent screening sessions, policy events, and APIs.
+- [Credential Sharing](${SITE_URL}/credential-sharing): Source/target credential diffs, approval, sync, rollback, and audit.
+
+## Company & legal
+
+- [About](${SITE_URL}/about): What LogicSRC is and who maintains it (Profullstack, Inc.).
+- [Hire Us](${SITE_URL}/hire-us): Implementation help at $250/week for accepted LogicSRC work.
+- [Terms](${SITE_URL}/terms)
+- [Privacy](${SITE_URL}/privacy)
+`;
+  return new Response(body, {
+    headers: {
+      "content-type": "text/plain; charset=utf-8",
+      "cache-control": "public, max-age=3600",
+    },
+  });
+}