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

crates/skald-core/src/mcp/mod.rs

@@ -268,6 +268,17 @@ impl McpManager {
         self.descriptions.write().unwrap().remove(name);
     }
 
+    /// Stops **every** running server (each dropped client → `kill_on_drop` kills
+    /// its child process) and forgets them. Used when a per-user container is
+    /// recreated (§6 remount): the old `docker exec -i` children are bound to the
+    /// now-gone container, so they must be torn down before reconnecting against
+    /// the fresh one via [`connect_all`](Self::connect_all).
+    pub fn stop_all(&self) {
+        self.servers.write().unwrap().clear();
+        self.errors.write().unwrap().clear();
+        self.descriptions.write().unwrap().clear();
+    }
+
     pub fn tools(&self) -> Vec<McpTool> {
         self.servers.read().unwrap().values()
             .flat_map(|s| s.tools().iter().cloned())