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/Tabs.tsx

@@ -0,0 +1,93 @@
+import React, { useMemo, useState } from 'react';
+
+export type TabItem = {
+  key: string;
+  title: React.ReactNode;
+  content: React.ReactNode;
+  disabled?: boolean;
+};
+
+export type TabsProps = {
+  items: TabItem[];
+  defaultActiveKey?: string;
+  activeKey?: string;
+  onChange?: (key: string) => void;
+  variant?: 'tabs' | 'pills';
+  fill?: boolean;
+  justify?: boolean;
+  className?: string;
+  navClassName?: string;
+  contentClassName?: string;
+};
+
+export function Tabs({
+  items,
+  defaultActiveKey,
+  activeKey,
+  onChange,
+  variant = 'tabs',
+  fill,
+  justify,
+  className = '',
+  navClassName = '',
+  contentClassName = ''
+}: TabsProps) {
+  const fallbackKey = items.find(i => !i.disabled)?.key;
+  const [internalKey, setInternalKey] = useState<string | undefined>(defaultActiveKey ?? fallbackKey);
+  const currentKey = activeKey ?? internalKey ?? fallbackKey;
+
+  const navClasses = useMemo(() => {
+    return [
+      'nav',
+      variant === 'tabs' ? 'nav-tabs' : 'nav-pills',
+      fill ? 'nav-fill' : '',
+      justify ? 'nav-justified' : '',
+      navClassName
+    ]
+      .filter(Boolean)
+      .join(' ');
+  }, [variant, fill, justify, navClassName]);
+
+  const handleSelect = (key: string, disabled?: boolean) => {
+    if (disabled) return;
+    if (!activeKey) {
+      setInternalKey(key);
+    }
+    onChange?.(key);
+  };
+
+  return (
+    <div className={className}>
+      <ul className={navClasses}>
+        {items.map(item => {
+          const isActive = item.key === currentKey;
+          return (
+            <li className="nav-item" key={item.key}>
+              <button
+                type="button"
+                className={`nav-link ${isActive ? 'active' : ''} ${item.disabled ? 'disabled' : ''}`.trim()}
+                onClick={() => handleSelect(item.key, item.disabled)}
+              >
+                {item.title}
+              </button>
+            </li>
+          );
+        })}
+      </ul>
+      <div className={`tab-content ${contentClassName}`.trim()}>
+        {items.map(item => {
+          const isActive = item.key === currentKey;
+          return (
+            <div
+              key={item.key}
+              className={`tab-pane fade ${isActive ? 'show active' : ''}`.trim()}
+              role="tabpanel"
+            >
+              {isActive ? item.content : null}
+            </div>
+          );
+        })}
+      </div>
+    </div>
+  );
+}