feat: self-portaling DetailPanel via AppShell portal target

DetailPanel now uses createPortal to render itself into
#cameleer-detail-panel-root, a div that AppShell places as a
direct sibling of .main in the top-level flex row. This means
pages can render <DetailPanel> anywhere in their JSX and it
automatically appears at the correct layout position.

AppShell's detail prop is deprecated and ignored — the portal
handles positioning automatically.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@cameleer/design-system",
-  "version": "0.1.3",
+  "version": "0.1.5",
   "type": "module",
   "main": "./dist/index.es.js",
   "module": "./dist/index.es.js",

src/design-system/composites/DetailPanel/DetailPanel.tsx

@@ -1,4 +1,5 @@
 import { useState, type ReactNode } from 'react'
+import { createPortal } from 'react-dom'
 import styles from './DetailPanel.module.css'
 
 interface Tab {
@@ -22,7 +23,7 @@ export function DetailPanel({ open, onClose, title, tabs, children, actions, cla
 
   const activeContent = tabs?.find((t) => t.value === activeTab)?.content
 
-  return (
+  const panel = (
     <aside
       className={`${styles.panel} ${open ? styles.open : ''} ${className ?? ''}`}
       aria-hidden={!open}
@@ -65,4 +66,8 @@ export function DetailPanel({ open, onClose, title, tabs, children, actions, cla
       )}
     </aside>
   )
+
+  // Portal to AppShell level if target exists, otherwise render in place
+  const portalTarget = document.getElementById('cameleer-detail-panel-root')
+  return portalTarget ? createPortal(panel, portalTarget) : panel
 }

src/design-system/layout/AppShell/AppShell.tsx

@@ -4,17 +4,18 @@ import type { ReactNode } from 'react'
 interface AppShellProps {
   sidebar: ReactNode
   children: ReactNode
+  /** @deprecated DetailPanel now portals itself automatically. This prop is ignored. */
   detail?: ReactNode
 }
 
-export function AppShell({ sidebar, children, detail }: AppShellProps) {
+export function AppShell({ sidebar, children }: AppShellProps) {
   return (
     <div className={styles.app}>
       {sidebar}
       <div className={styles.main}>
         {children}
       </div>
-      {detail}
+      <div id="cameleer-detail-panel-root" />
     </div>
   )
 }