P0: Next.js shell — tokens, motion, SlidePanel, LeftRail, auth plumbing

- Tailwind v4 @theme block encoding all spec §2 tokens; full §3 keyframe
  inventory with prefers-reduced-motion handling; Geist vendored (air-gap)
- SlidePanel width-animation primitive (component-tested: exit-transition
  unmount, fixed-width inner content, a11y region semantics)
- session-key.ts mirroring the Rust codec + URL-param encoding; nuqs
  panel-params with spec ?sessions=1 flag shape and routines->scheduled alias
- Zod-typed API client; httpOnly cookie session bridge (/auth/session);
  login page; (workspace) layout with LeftRail roster/nav/user; Team and
  Credits pages on real endpoints (+ GET /api/team/members in tc-api)
- Vitest + Testing Library harness (26 tests); ESLint max-lines 1250 +
  no-warning-comments mirroring the CI gates

Co-Authored-By: Claude Fable 5 <[email protected]>

frontend/src/app/(workspace)/page.tsx

@@ -0,0 +1,11 @@
+// Workspace home: the empty-shell landing until agent chat arrives (P1).
+export default function WorkspaceHome() {
+  return (
+    <section className="flex h-dvh flex-col items-center justify-center gap-2 motion-safe:animate-[route-fade-in_var(--duration-normal)_var(--ease-app)]">
+      <h1 className="text-xxxl font-semibold tracking-tight">TeamClaw</h1>
+      <p className="text-sm text-muted-foreground">
+        Pick a claw from the rail, or create one to get started.
+      </p>
+    </section>
+  );
+}