feat: rename keep-notes to memento-note, migrate to PostgreSQL, fix MCP bugs

- Rename directory keep-notes -> memento-note with all code references
- Prisma: SQLite -> PostgreSQL (both app and MCP server schemas)
- Sync MCP schema with main app (add missing fields, relations, indexes)
- Delete 17 SQLite migrations (clean slate for PostgreSQL)
- Remove SQLite dependencies (@libsql/client, better-sqlite3, etc.)
- Fix MCP server: hardcoded Windows DB paths -> DATABASE_URL env var
- Fix MCP server: .dockerignore excluded index-sse.js (SSE mode broken)
- MCP Dockerfile: node:20 -> node:22
- Docker Compose: add postgres service, remove SQLite volume
- Generate favicon.ico, icon-192.png, icon-512.png, apple-icon.png
- Update layout.tsx icons and manifest.json for PNG icons
- Update all .env files for PostgreSQL
- Rewrite README.md with updated sections
- Remove mcp-server/node_modules and prisma/client-generated from git tracking

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

memento-note/app/(main)/admin/layout.tsx

@@ -0,0 +1,23 @@
+import { AdminSidebar } from '@/components/admin-sidebar'
+import { AdminContentArea } from '@/components/admin-content-area'
+import { auth } from '@/auth'
+import { redirect } from 'next/navigation'
+
+export default async function AdminLayout({
+  children,
+}: {
+  children: React.ReactNode
+}) {
+  const session = await auth()
+
+  if ((session?.user as any)?.role !== 'ADMIN') {
+    redirect('/')
+  }
+
+  return (
+    <div className="flex min-h-screen bg-gray-50 dark:bg-zinc-950">
+      <AdminSidebar />
+      <AdminContentArea>{children}</AdminContentArea>
+    </div>
+  )
+}