feat: comprehensive SEO — meta tags, OG, Twitter cards, JSON-LD, sitemap, robots, llms.txt

Adds metadataBase, full OpenGraph + Twitter card tags, keywords,
JSON-LD structured data (SoftwareApplication + Organization),
sitemap.ts, robots.ts with AI crawler directives, and llms.txt
for AI agent discoverability.

apps/web/src/app/layout.tsx

@@ -5,8 +5,63 @@ import "./globals.css";
 const inter = Inter({ subsets: ["latin"] });
 
 export const metadata: Metadata = {
-  title: "AgentLens",
-  description: "Agent observability that traces decisions, not just API calls",
+  metadataBase: new URL("https://agentlens.vectry.tech"),
+  title: {
+    default: "AgentLens — Agent Observability Platform",
+    template: "%s | AgentLens",
+  },
+  description:
+    "Open-source agent observability that traces decisions, not just API calls. Monitor AI agent reasoning, tool selection, and routing in real-time.",
+  keywords: [
+    "agent observability",
+    "AI monitoring",
+    "LLM tracing",
+    "agent decisions",
+    "AI debugging",
+    "tool selection tracing",
+    "multi-agent observability",
+    "open source",
+  ],
+  authors: [{ name: "Vectry" }],
+  creator: "Vectry",
+  openGraph: {
+    type: "website",
+    locale: "en_US",
+    url: "https://agentlens.vectry.tech",
+    siteName: "AgentLens",
+    title: "AgentLens — Agent Observability Platform",
+    description:
+      "Open-source agent observability that traces decisions, not just API calls. Monitor AI agent reasoning, tool selection, and routing in real-time.",
+    images: [
+      {
+        url: "/og-image.png",
+        width: 1200,
+        height: 630,
+        alt: "AgentLens — Agent Observability Platform",
+      },
+    ],
+  },
+  twitter: {
+    card: "summary_large_image",
+    title: "AgentLens — Agent Observability Platform",
+    description:
+      "Open-source agent observability that traces decisions, not just API calls. Monitor AI agent reasoning, tool selection, and routing in real-time.",
+    images: ["/og-image.png"],
+  },
+  robots: {
+    index: true,
+    follow: true,
+    googleBot: {
+      index: true,
+      follow: true,
+      "max-video-preview": -1,
+      "max-image-preview": "large",
+      "max-snippet": -1,
+    },
+  },
+  alternates: {
+    canonical: "https://agentlens.vectry.tech",
+  },
 };
 
 export default function RootLayout({