Add author auth, forking, tags, and stats tracking

Introduce token-based author authentication (register/verify API),
   skill forking with EditGate protection, tag metadata on skills,
   and download/push stats. Enhanced push scripts with token auth
   and per-skill filtering. Updated UI with stats, tags, and
   author info on skill cards.

src/pages/[slug]/i.ts

@@ -0,0 +1,36 @@
+import type { APIRoute } from 'astro';
+import { getSkill } from '../../lib/skills';
+import { isPowerShell } from '../../lib/sync';
+
+export const GET: APIRoute = async ({ params, url, request }) => {
+  const { slug } = params;
+  const skill = await getSkill(slug!);
+  if (!skill) {
+    return new Response('Skill not found', { status: 404 });
+  }
+
+  const origin = url.origin;
+  const ps = isPowerShell(request);
+
+  const script = ps
+    ? [
+        '$ErrorActionPreference = "Stop"',
+        '$Dir = ".claude\\skills"',
+        'New-Item -ItemType Directory -Force -Path $Dir | Out-Null',
+        `Invoke-WebRequest -Uri "${origin}/${slug}" -OutFile (Join-Path $Dir "${slug}.md")`,
+        `Write-Host "✓ Installed ${skill.name} to $Dir\\${slug}.md"`,
+        '',
+      ].join('\n')
+    : [
+        '#!/usr/bin/env bash',
+        'set -euo pipefail',
+        'mkdir -p .claude/skills',
+        `curl -fsSL "${origin}/${slug}" -o ".claude/skills/${slug}.md"`,
+        `echo "✓ Installed ${skill.name} to .claude/skills/${slug}.md"`,
+        '',
+      ].join('\n');
+
+  return new Response(script, {
+    headers: { 'Content-Type': 'text/plain; charset=utf-8' },
+  });
+};