Major rebranding, i18n, dashboard, shared folders, role capabilities

- Rebrand: new app/agent icons, SKALD.md, warm "paper" CSS palette
  (terracotta accent, --radius tokens, WCAG contrast, reduced-motion),
  updated favicon, tray icon, skaldkonur asset
- i18n: backend crate (i18n.rs, locale column, ui_locale config),
  frontend library (web/lib/i18n.js, I18nMixin, t(key)),
  translation files (web/i18n/), every component wired
- Dashboard: <dashboard-page> replaces old home-page content;
  <app-copilot> becomes the landing page (full/dock layout modes)
- Shared folders: API endpoints (shared_folders.rs), frontend page,
  can_write membership, container mount topology, user_fs routing
- Role capabilities: new db table & authorization seam (data not enums),
  roles.attrs JSON for ui_mode / interface select
- Setup: skald-setup prompts for language + password, sets ui_locale
- General: components migrated to CSS variables, Lit conventions cleanup,
  connectors/catalog/marketplace/approval refactoring

web/css/users-roles.css

@@ -71,7 +71,7 @@
   font-weight: 600;
 }
 
-.um-badge-encrypted { background: rgba(99, 102, 241, .15);  color: #6366f1; }
+.um-badge-encrypted { background: rgba(var(--accent-rgb), .15);  color: var(--accent); }
 .um-badge-clear     { background: rgba(108, 117, 125, .15); color: #6c757d; }
 .um-badge-active    { background: rgba(25, 135, 84, .15);   color: #198754; }
 .um-badge-inactive  { background: rgba(220, 53, 69, .15);   color: #dc3545; }