feat(hub): migrate database admin pages to SPA (database-admin)

- scaffold hub/database-admin as SvelteKit 2 + Svelte 5 static SPA
  with aurora/glass visual style (paths.base='/database')
- add lib/{api,session,org}.ts + Aurora.svelte component
- add routes: root redirect, /admin login page, /dashboard (OWNER/ADMIN only)
- backend: replace server-rendered HTML routes with /database/config JSON endpoint
- add hub/src/database/static.ts to serve SPA under /database/*
- wire registerDatabaseSpa into plugin.ts
- exempt /database/* from silo rate-limit (same treatment as /admin/*)
- add database:dev + database:build npm scripts; update deploy scripts
- update hub/src/database/README.md

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

hub/database-admin/vite.config.ts

@@ -0,0 +1,17 @@
+import { sveltekit } from '@sveltejs/kit/vite';
+import tailwindcss from '@tailwindcss/vite';
+import { defineConfig } from 'vite';
+
+export default defineConfig({
+	plugins: [tailwindcss(), sveltekit()],
+	server: {
+		proxy: {
+			'/api': 'http://127.0.0.1:8788',
+			'/auth': 'http://127.0.0.1:8788',
+			// Backend owns the /database/* HTTP surface (login page, dashboard,
+			// data routes). Proxy it in dev so those paths hit the real server
+			// instead of the SPA fallback.
+			'/database': 'http://127.0.0.1:8788',
+		},
+	},
+});