Move allauth + auth UI to legacy/

allauth/ (44 files) is a django-allauth React UI — a separate concern
from the Mizan protocol. Moved to legacy/ pending extraction into a
standalone mizan-django-allauth package.

Also moved to legacy/:
- client/AuthContext.tsx — generic auth state from /me endpoint
- client/RouterContext.tsx — framework-agnostic router adapter
- client/routing.tsx — UserRoute/StaffRoute/AnonymousRoute guards
- client/nextjs.tsx — Next.js router adapter for auth

These are auth UI infrastructure, not Mizan protocol. The Mizan core
only needs JWT for auth header selection (jwt/ stays — MizanProvider
depends on useJWT() to decide between Bearer and session auth).

Cleaned up re-exports in client/react.ts and vitest aliases.

33 React tests pass.

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

legacy/allauth/components/ProviderList.tsx

@@ -0,0 +1,56 @@
+'use client'
+
+import { useConfig } from '../contexts/AuthContext'
+import { useAllauthAPI } from '../contexts/APIContext'
+import { useStyles } from '../contexts/StylesContext'
+
+interface Provider {
+    id: string
+    name: string
+}
+
+interface ProviderListProps {
+    callbackUrl: string
+    process?: 'login' | 'connect'
+}
+
+export function ProviderList({ callbackUrl, process = 'login' }: ProviderListProps) {
+    const config = useConfig()
+    const api = useAllauthAPI()
+    const styles = useStyles()
+
+    const providers: Provider[] = config?.data?.socialaccount?.providers || []
+
+    if (providers.length === 0) {
+        return null
+    }
+
+    const handleProviderClick = (providerId: string) => {
+        const provider = api.oauth.provider(providerId)
+        if (process === 'connect') {
+            provider.connect.withRedirect(callbackUrl)
+        } else {
+            provider.login.withRedirect(callbackUrl)
+        }
+    }
+
+    return (
+        <div className={styles.providersContainer}>
+            <div className={styles.divider}>
+                <span className={styles.dividerText}>or continue with</span>
+            </div>
+            <div className={styles.providerButtons}>
+                {providers.map((provider) => (
+                    <button
+                        key={provider.id}
+                        type="button"
+                        onClick={() => handleProviderClick(provider.id)}
+                        className={styles.providerButton}
+                    >
+                        {provider.name}
+                    </button>
+                ))}
+            </div>
+        </div>
+    )
+}