feat(web): design system — ms-* tokens, ThemeProvider, MosaicLogo, sidebar (#221)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

apps/web/src/components/layout/topbar.tsx

@@ -1,42 +1,87 @@
 'use client';
 
-import { usePathname, useRouter } from 'next/navigation';
-import { useSession, signOut } from '@/lib/auth-client';
+import { useRouter } from 'next/navigation';
+import { signOut, useSession } from '@/lib/auth-client';
+import { ThemeToggle } from './theme-toggle';
+import { useSidebar } from './sidebar-context';
+
+function MenuIcon(): React.JSX.Element {
+  return (
+    <svg
+      width="16"
+      height="16"
+      viewBox="0 0 16 16"
+      fill="none"
+      stroke="currentColor"
+      strokeWidth="1.5"
+    >
+      <path d="M2 4h12M2 8h12M2 12h12" />
+    </svg>
+  );
+}
 
 export function Topbar(): React.ReactElement {
   const { data: session } = useSession();
   const router = useRouter();
-  const pathname = usePathname();
-
-  if (pathname.startsWith('/chat')) {
-    return <></>;
-  }
+  const { isMobile, mobileOpen, setMobileOpen, toggleCollapsed } = useSidebar();
 
   async function handleSignOut(): Promise<void> {
     await signOut();
     router.replace('/login');
   }
 
-  return (
-    <header className="sticky top-0 z-20 flex h-14 items-center justify-between border-b border-surface-border bg-surface-card/80 px-6 backdrop-blur-sm">
-      <div />
+  function handleSidebarToggle(): void {
+    if (isMobile) {
+      setMobileOpen(!mobileOpen);
+      return;
+    }
 
-      <div className="flex items-center gap-4">
+    toggleCollapsed();
+  }
+
+  return (
+    <header
+      className="app-header justify-between border-b px-4 md:px-6"
+      style={{
+        height: 'var(--topbar-h)',
+        background: 'color-mix(in srgb, var(--surface) 88%, transparent)',
+        borderBottomColor: 'var(--border)',
+      }}
+    >
+      <div className="flex items-center gap-3">
+        <button
+          type="button"
+          onClick={handleSidebarToggle}
+          className="btn-ghost rounded-lg border p-2"
+          style={{ borderColor: 'var(--border)', color: 'var(--text-2)' }}
+          aria-label="Toggle sidebar"
+        >
+          <MenuIcon />
+        </button>
+        <div className="hidden sm:block">
+          <div className="text-sm font-medium text-[var(--text)]">Workspace</div>
+          <div className="text-xs text-[var(--muted)]">Unified agent operations</div>
+        </div>
+      </div>
+
+      <div className="flex items-center gap-3">
+        <ThemeToggle />
         {session?.user ? (
           <>
-            <span className="text-sm text-text-secondary">
+            <span className="hidden text-sm text-[var(--text-2)] sm:block">
               {session.user.name ?? session.user.email}
             </span>
             <button
               type="button"
               onClick={handleSignOut}
-              className="rounded-md px-3 py-1.5 text-sm text-text-muted transition-colors hover:bg-surface-elevated hover:text-text-primary"
+              className="rounded-md px-3 py-1.5 text-sm transition-colors"
+              style={{ color: 'var(--muted)' }}
             >
               Sign out
             </button>
           </>
         ) : (
-          <span className="text-sm text-text-muted">Not signed in</span>
+          <span className="text-sm text-[var(--muted)]">Not signed in</span>
         )}
       </div>
     </header>