chore: initialize @limitless/ui git repo + add AppShell

This brings the long-untracked @limitless/ui source tree under version
control. Until now /srv/k8s/templates/limitless-ui has been a plain
file: dependency consumed by gscChronos / gscCRM / gscAdmin, with
copies scattered across web/gsc{Portal,WWW,Aether,Register}/ and
apps/gsc{Meet,Share}/. None were git-tracked.

Treating /srv/k8s/templates/limitless-ui as the canonical going
forward; secondary copies should be replaced with this version
in their consumers' Dockerfiles when they next get touched.

Changes in this initial commit beyond the snapshot:
- Add src/layout/AppShell.tsx — runtime-loaded chrome (header,
  sidebar, footer) backed by gsc-shell-api. Public surface:
    AppShell, ShellProvider, useShell, ShellConfig types
  Framework-agnostic (no Next.js dep). Apps pass appKey + apiUrl +
  getToken; AppShell composes the existing PageShell / Navbar /
  Sidebar / Footer primitives with API data.
- Re-export AppShell from src/index.ts.
- Fix build script: `tsc -p tsconfig.json --noEmit false`. The bare
  `tsc` command was a no-op because tsconfig.json sets noEmit:true
  for typecheck speed. Existing dist/ only existed because of an
  earlier emit; clean rebuilds were silently broken.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/components/Nav.tsx

@@ -0,0 +1,60 @@
+import React from 'react';
+
+export type NavItem = {
+  key: string;
+  label: React.ReactNode;
+  href?: string;
+  active?: boolean;
+  disabled?: boolean;
+  onClick?: () => void;
+};
+
+export type NavProps = {
+  items: NavItem[];
+  variant?: 'tabs' | 'pills' | 'underline';
+  fill?: boolean;
+  justify?: boolean;
+  vertical?: boolean;
+  className?: string;
+};
+
+export function Nav({ items, variant = 'tabs', fill, justify, vertical, className = '' }: NavProps) {
+  const classes = [
+    'nav',
+    variant === 'tabs' ? 'nav-tabs' : variant === 'pills' ? 'nav-pills' : 'nav-underline',
+    fill ? 'nav-fill' : '',
+    justify ? 'nav-justified' : '',
+    vertical ? 'flex-column' : '',
+    className
+  ]
+    .filter(Boolean)
+    .join(' ');
+
+  return (
+    <ul className={classes}>
+      {items.map(item => (
+        <li className="nav-item" key={item.key}>
+          {item.href ? (
+            <a
+              className={`nav-link ${item.active ? 'active' : ''} ${item.disabled ? 'disabled' : ''}`.trim()}
+              href={item.href}
+              onClick={item.onClick}
+              aria-disabled={item.disabled}
+            >
+              {item.label}
+            </a>
+          ) : (
+            <button
+              type="button"
+              className={`nav-link ${item.active ? 'active' : ''} ${item.disabled ? 'disabled' : ''}`.trim()}
+              onClick={item.onClick}
+              disabled={item.disabled}
+            >
+              {item.label}
+            </button>
+          )}
+        </li>
+      ))}
+    </ul>
+  );
+}