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>

scripts/postbuild.cjs

@@ -0,0 +1,66 @@
+/* Post-build: copy CSS and fix ESM import extensions */
+const fs = require('fs');
+const path = require('path');
+
+const distDir = path.join(__dirname, '..', 'dist');
+
+// Copy CSS
+const cssSrc = path.join(__dirname, '..', 'src', 'styles.css');
+const cssDest = path.join(distDir, 'styles.css');
+fs.copyFileSync(cssSrc, cssDest);
+
+// Fix ESM imports by adding .js extensions
+function fixImports(dir) {
+  const entries = fs.readdirSync(dir, { withFileTypes: true });
+  for (const entry of entries) {
+    const fullPath = path.join(dir, entry.name);
+    if (entry.isDirectory()) {
+      fixImports(fullPath);
+    } else if (entry.name.endsWith('.js')) {
+      let content = fs.readFileSync(fullPath, 'utf8');
+
+      // Function to determine the correct extension
+      const addExtension = (match, prefix, importPath, quote) => {
+        // Check if the import path already has .js extension
+        if (importPath.endsWith('.js')) {
+          return match;
+        }
+
+        // Check if this is a directory with an index.js
+        const baseDir = path.dirname(fullPath);
+        const targetPath = path.resolve(baseDir, importPath);
+
+        // Check if it's a directory with index.js
+        if (fs.existsSync(targetPath) && fs.statSync(targetPath).isDirectory()) {
+          if (fs.existsSync(path.join(targetPath, 'index.js'))) {
+            return `${prefix}${importPath}/index.js${quote}`;
+          }
+        }
+
+        // Check if adding .js makes it a valid file
+        if (fs.existsSync(targetPath + '.js')) {
+          return `${prefix}${importPath}.js${quote}`;
+        }
+
+        return match;
+      };
+
+      // Fix 'from' imports
+      content = content.replace(
+        /(from\s+['"])(\.\.?\/[^'"]+)(['"])/g,
+        addExtension
+      );
+
+      // Fix 'export * from' statements
+      content = content.replace(
+        /(export\s+\*\s+from\s+['"])(\.\.?\/[^'"]+)(['"])/g,
+        addExtension
+      );
+
+      fs.writeFileSync(fullPath, content);
+    }
+  }
+}
+
+fixImports(distDir);
+console.log('Post-build: CSS copied and ESM imports fixed');