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/src/database/plugin.ts

@@ -16,6 +16,7 @@
 import type { FastifyInstance } from "fastify";
 import type { PrismaClient } from "@prisma/client";
 import { registerDatabaseRoutes } from "./routes/databaseRoutes.js";
+import { registerDatabaseSpa } from "./static.js";
 
 export interface DatabasePluginConfig {
   readonly prisma: PrismaClient;
@@ -42,4 +43,8 @@ export async function registerDatabasePlugin(
     siloOrganizationSlug: config.siloOrganizationSlug,
     allowDevLoginBypass,
   });
+
+  // SPA shell + fallback, registered after the concrete /database/* routes above
+  // so the /database/* wildcard does not shadow them.
+  await registerDatabaseSpa(app);
 }