Add Buckets, Monitoring, Memberships, Networking, SSO, Announcements, Status page

Full set of admin surfaces on top of /platform/* and /admin/* endpoints,
plus a migration of /assistant onto @crema/llm-providers-ui.

Buckets (/buckets):
  S3-level CRUD over /platform/buckets — list, create, delete (with the
  6-digit confirmation flow the backend enforces), per-bucket configure
  for versioning / CORS rules / policy JSON, plus an object browser
  with FileGrid/FileList from @crema/file-ui and presigned-URL reveal.
  Storage-config picker scopes the view to one credential at a time.

Monitoring (/monitoring):
  Live dashboard. Service health board derived from indirect signals
  (status-ui OverallStatus + ComponentRow). KPI tiles for sessions,
  jobs, audit. Tabs: background jobs (Donut + BarChart + retry recent),
  sessions (Sparkline of last 24h sign-ins), audit activity (BarChart
  of severity / top resource types), infrastructure (DO summary +
  WorldMapSvg coloured by droplet region + droplet list + Spaces),
  rate limits. 30s auto-refresh.

Memberships (/memberships):
  M:N glue between users and tenants over /admin/memberships. Add /
  edit / suspend / activate / remove with role multi-select.

Networking (/networking):
  Tabs over /platform/{firewalls,vpcs,domains,floating_ips}.
  Read/delete on firewalls, read on VPCs, full DNS-record CRUD, and
  inline assign/unassign for floating IPs.

SSO (/sso):
  /sso/identity-providers CRUD with PEM cert as write-only field, plus
  /sso/sessions list with destroy.

Announcements (/announcements):
  /admin/announcements CRUD. Platform-wide vs per-tenant audience,
  schedule windows, dismissible + active toggles.

Status page (/status-page):
  /admin/status-page/{components,incidents,subscribers}. Components
  CRUD, incidents with timeline + post-update + resolve flow,
  subscriber list. Public preview at the top using StatusBoard +
  IncidentTimeline from @crema/status-ui.

Assistant migration:
  /assistant now uses @crema/llm-providers-ui (provider catalog +
  vault key resolution) instead of ~/lib/llm-settings. Same async
  buildAdapter() flow used by /ai. The legacy lib file is now
  unreferenced and can be removed when ready.

New sibling libs wired (cloned from CremaUIStudio):
  lib-file-ui, lib-card-ui, lib-dashboard-ui, lib-chart-ui,
  lib-map-ui, lib-status-ui.

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

app/app.css

@@ -19,6 +19,12 @@
 @source "../../lib-auth-ui/src";
 @source "../../lib-agent-ui/src";
 @source "../../lib-llm-providers-ui/src";
+@source "../../lib-file-ui/src";
+@source "../../lib-card-ui/src";
+@source "../../lib-dashboard-ui/src";
+@source "../../lib-chart-ui/src";
+@source "../../lib-map-ui/src";
+@source "../../lib-status-ui/src";
 /* CREMA:SOURCES */
 
 @custom-variant dark (&:is(.dark *));