init: arcadia-admin — admin webapp for arcadia-core, cloned from vibespace

Initial commit. Spun up via the docs/STARTER.md recipe: cp from vibespace,
reset git, rename package, set brand to "Arcadia Admin" with Shield icon
in app/lib/identity.ts.

Inherits the full Crema sibling-lib wiring including @crema/arcadia-client
(typed HTTP + Phoenix Channels realtime against arcadia-core) and
@crema/arcadia-auth-ui (login/signup/password-reset/2FA forms). The /login
route already renders <LoginForm>; <ArcadiaProvider> in app/root.tsx reads
VITE_ARCADIA_URL (default localhost:4000) and VITE_ARCADIA_TENANT (default
"default").

CLAUDE.md and README rewritten to frame this as the admin app for
arcadia-core. docs/STARTER.md removed — arcadia-admin is a leaf consumer,
not a downstream starter.

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

vitest.config.ts

@@ -0,0 +1,13 @@
+import { defineConfig } from "vitest/config"
+import tsconfigPaths from "vite-tsconfig-paths"
+
+export default defineConfig({
+  plugins: [tsconfigPaths()],
+  test: {
+    environment: "jsdom",
+    globals: true,
+    setupFiles: ["./vitest.setup.ts"],
+    include: ["app/**/*.{test,spec}.{ts,tsx}"],
+    css: false,
+  },
+})