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/home.css

@@ -1,6 +1,6 @@
-/* ── Home page ─────────────────────────────────────────────────────────────── */
+/* ── Dashboard page ────────────────────────────────────────────────────────── */
 
-home-page {
+dashboard-page {
   display: none;
   flex-direction: column;
   flex: 1;
@@ -13,34 +13,6 @@ home-page {
   box-sizing: border-box;
 }
 
-/* ── Debug toggle ──────────────────────────────────────────────────────────── */
-
-.home-debug-bar {
-  display: flex;
-  justify-content: flex-end;
-  margin-bottom: 0.75rem;
-}
-
-.home-debug-toggle {
-  display: flex;
-  align-items: center;
-  gap: 6px;
-  font-size: 0.78rem;
-  font-weight: 500;
-  color: var(--bs-secondary-color);
-  cursor: pointer;
-  user-select: none;
-  padding: 4px 8px;
-  border-radius: 6px;
-  transition: background 0.15s;
-}
-
-.home-debug-toggle:hover {
-  background: var(--bs-tertiary-bg);
-}
-
-.home-debug-toggle i { font-size: 0.82rem; }
-
 /* ── Hero ──────────────────────────────────────────────────────────────────── */
 
 .home-hero {