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>

public/scripts/demo-search.script

@@ -0,0 +1,7 @@
+# Demo: focus and fill the appbar search
+# speed: 1
+
+click appbar-search
+fill appbar-search "hello from a script"
+wait 1200
+fill appbar-search ""

public/scripts/demo-tour.script

@@ -0,0 +1,28 @@
+# Comfy Cloud — short tour through the rail
+# speed: 0.9
+
+# Open the rail so labels are visible
+click sidebar-toggle
+wait 500
+
+# Visit each section
+click nav-resources
+wait_for nav-resources
+wait 500
+
+click nav-activity
+wait 500
+
+click nav-assistant
+wait 700
+
+click nav-library
+wait 500
+
+click nav-settings
+wait 500
+
+# Back home, collapse rail
+click nav-overview
+wait 400
+click sidebar-toggle