Add user authentication with login/register

- Add users and sessions tables to database schema
- Add bcryptjs for password hashing
- Create auth API routes (login, register, logout, me)
- Add AuthProvider context for client-side auth state
- Update all API routes to require authentication and filter by userId
- Create login and register pages
- Add AppShell component for authenticated layout
- Update all pages to use AppShell and show user info
- Each user now has their own private entries and tags

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

src/app/settings/page.tsx

@@ -1,14 +1,37 @@
+"use client";
+
+import { AppShell } from "@/components/AppShell";
+import { useAuth } from "@/components/AuthProvider";
 import { APP_NAME } from "@/lib/constants";
+import { LogOut } from "lucide-react";
 
 export default function SettingsPage() {
+  const { user, logout } = useAuth();
+
   return (
-    <div>
+    <AppShell>
       <header className="mb-8">
         <h1 className="text-2xl font-light">{APP_NAME}</h1>
         <p className="text-sm text-muted">Settings</p>
       </header>
 
       <div className="space-y-6">
+        {/* Account info */}
+        {user && (
+          <div className="p-4 bg-surface border border-border rounded-xl">
+            <h3 className="font-medium mb-1">Account</h3>
+            <p className="text-sm text-muted">{user.email}</p>
+            {user.name && <p className="text-sm text-muted">{user.name}</p>}
+            <button
+              onClick={logout}
+              className="mt-3 flex items-center gap-2 text-sm text-red-400 hover:text-red-300"
+            >
+              <LogOut size={16} />
+              Sign out
+            </button>
+          </div>
+        )}
+
         {/* Notifications - disabled in MVP */}
         <div className="p-4 bg-surface border border-border rounded-xl opacity-50">
           <div className="flex items-center justify-between">
@@ -68,6 +91,6 @@ export default function SettingsPage() {
           <p className="mt-1">A calm, private gratitude log.</p>
         </div>
       </div>
-    </div>
+    </AppShell>
   );
 }