feat(arcrun): mira wiki page with tag filter + accumulated WIP

- landing/app/mira/wiki: tag=mira-wiki list now shows all wiki paragraphs
  (depends on KBDB tag filter exposed in matrix/kbdb commit, separate repo)
- landing: app/mira hub + feed split + various WIP from prior sessions
- registry/components: claude_api / kbdb_create_block / kbdb_get / km_writer /
  platform_crypto / auth_oauth2 contracts + main.go (accumulated)
- .component-builds: pkg-lock updates + index.ts adjustments (WIP)
- .agents/specs/arcrun/frontend-redesign: design notes
- docs/test_credentials, docs/user_requirements/arcrun-landing-page: WIP docs
- cypher-executor: auth-dispatcher / wasi-shim adjustments (WIP)

Includes accumulated work from prior sessions plus the wiki UI tag-filter
update that surfaces the AI-generated wiki paragraphs at /mira/wiki.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

landing/app/page.tsx

@@ -1,7 +1,8 @@
 'use client';
 
-import { useState } from 'react';
+import { useState, useEffect } from 'react';
 import Link from 'next/link';
+import SiteNav from './components/SiteNav';
 
 const API_BASE = process.env.NEXT_PUBLIC_API_BASE ?? 'https://cypher.arcrun.dev';
 
@@ -55,23 +56,17 @@ Content-Type: application/json
 
 export default function HomePage() {
   const [activeTab, setActiveTab] = useState<'python' | 'javascript' | 'http'>('python');
+  const [isLoggedIn, setIsLoggedIn] = useState(false);
+
+  useEffect(() => {
+    fetch(`${API_BASE}/me`, { credentials: 'include' })
+      .then(r => { if (r.ok) setIsLoggedIn(true); })
+      .catch(() => {});
+  }, []);
 
   return (
     <div className="flex flex-col min-h-screen bg-[#0a0a0a] text-[#ededed]">
-      {/* Nav */}
-      <nav className="flex items-center justify-between px-6 py-4 border-b border-[#1a1a1a]">
-        <span className="text-white font-bold text-lg tracking-tight">arcrun</span>
-        <div className="flex items-center gap-4 text-sm">
-          <Link href="/integrations" className="text-[#666] hover:text-white transition-colors">Integrations</Link>
-          <Link href="/api-docs" className="text-[#666] hover:text-white transition-colors">API</Link>
-          <a href="https://github.com/richblack/arcrun" target="_blank" rel="noopener noreferrer"
-            className="text-[#666] hover:text-white transition-colors">GitHub</a>
-          <Link href="/login"
-            className="bg-indigo-600 hover:bg-indigo-500 text-white px-4 py-1.5 rounded-md text-sm font-medium transition-colors">
-            Get API Key
-          </Link>
-        </div>
-      </nav>
+      <SiteNav currentPath="/" />
 
       {/* Hero */}
       <section className="flex flex-col items-center text-center px-6 pt-24 pb-16">
@@ -92,9 +87,9 @@ export default function HomePage() {
         </p>
 
         <div className="flex gap-3 flex-wrap justify-center">
-          <Link href="/login"
+          <Link href={isLoggedIn ? '/dashboard' : '/login'}
             className="bg-indigo-600 hover:bg-indigo-500 text-white px-6 py-3 rounded-lg font-medium transition-colors">
-            Get API Key — Free
+            {isLoggedIn ? 'Go to Dashboard' : 'Get API Key — Free'}
           </Link>
           <a href="https://github.com/richblack/arcrun" target="_blank" rel="noopener noreferrer"
             className="border border-[#333] hover:border-[#555] text-[#aaa] hover:text-white px-6 py-3 rounded-lg font-medium transition-colors">
@@ -183,9 +178,9 @@ drive = auth.bind(
       <section className="border-t border-[#1a1a1a] py-16 text-center px-6">
         <h2 className="text-3xl font-bold text-white mb-3">準備好了嗎？</h2>
         <p className="text-[#555] mb-8">免費取得 API Key，不需要信用卡。</p>
-        <Link href="/login"
+        <Link href={isLoggedIn ? '/dashboard' : '/login'}
           className="bg-indigo-600 hover:bg-indigo-500 text-white px-8 py-3 rounded-lg font-medium transition-colors">
-          免費取得 API Key
+          {isLoggedIn ? 'Go to Dashboard' : '免費取得 API Key'}
         </Link>
       </section>