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/deploy/deploy_platform.sh

@@ -60,10 +60,11 @@ if [ "$release_ready" = false ]; then
     -e "ssh ${SSH_OPTS[*]}" \
     "$REPO_ROOT/hub/" "$DEPLOY_USER@$HOST:$HUB_DIR/"
 
-  # 2. Install deps (hub + admin-web), audit hub prod, build tsc + SPA, mark complete.
-  # `npm run build` → tsc then admin:build → admin-web/build for registerStaticSpa.
+  # 2. Install deps (hub + both SPAs), audit hub prod, build tsc + SPAs, mark complete.
+  # `npm run build` → tsc then admin:build + database:build → admin-web/build and
+  # database-admin/build for registerStaticSpa / registerDatabaseSpa.
   ssh "${SSH_OPTS[@]}" "$DEPLOY_USER@$HOST" \
-    "cd '$HUB_DIR' && PUPPETEER_SKIP_DOWNLOAD=1 npm ci && npm ci --prefix admin-web && npm run audit:production && npm run build && touch '$RELEASE_DIR/.complete'"
+    "cd '$HUB_DIR' && PUPPETEER_SKIP_DOWNLOAD=1 npm ci && npm ci --prefix admin-web && npm ci --prefix database-admin && npm run audit:production && npm run build && touch '$RELEASE_DIR/.complete'"
 fi
 
 # 3. Ensure the service is installed (idempotent), then restart.