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/session/handler/llm_loop.rs

@@ -431,7 +431,9 @@ impl ChatSessionHandler {
         let ctx = ToolContext {
             session_id: self.session_id,
             pool: Arc::clone(&self.db),
-            fs: Arc::clone(&self.fs),
+            // Snapshot the fs cell for the duration of this tool call — a concurrent
+            // shared-folder remount swaps the cell, the next call picks it up (§6).
+            fs: self.fs.load(),
         };
         self.tools.run(name, &ctx, args)
     }

crates/skald-core/src/session/handler/mod.rs

@@ -20,7 +20,7 @@ use crate::config::DatetimeConfig;
 use crate::db::{chat_history, chat_sessions_stack};
 use crate::events::ServerEvent;
 use core_api::message_meta::MessageMetadata;
-use core_api::user_fs::UserFs;
+use core_api::user_fs::SharedFs;
 use crate::llm::LlmManager;
 use crate::mcp::McpProvider;
 use crate::image_generate::ImageGeneratorManager;
@@ -272,8 +272,11 @@ pub struct ChatSessionHandler {
     pub(super) user_id:          String,
     /// The owner's filesystem view (home + shared folders + container), threaded
     /// into every [`ToolContext`] so disk fs-tools resolve per-user host paths and
-    /// `execute_cmd` execs into the owner's container (blueprint §6).
-    pub(super) fs:               Arc<UserFs>,
+    /// `execute_cmd` execs into the owner's container (blueprint §6). A **shared
+    /// swappable cell** (not a snapshot): a shared-folder membership change is
+    /// applied in place (§6 remount), so a live session picks it up on its next
+    /// tool call without being rebuilt — see [`SharedFs`].
+    pub(super) fs:               SharedFs,
     pub(super) llm_manager:      Arc<LlmManager>,
     pub(super) max_history_messages:  usize,
     pub(super) max_tool_rounds:       usize,
@@ -343,7 +346,7 @@ impl ChatSessionHandler {
         db:                    Arc<SqlitePool>,
         shared_pool:           Arc<SqlitePool>,
         user_id:               String,
-        fs:                    Arc<UserFs>,
+        fs:                    SharedFs,
         llm_manager:           Arc<LlmManager>,
         max_history_messages:  usize,
         max_tool_rounds:       usize,

crates/skald-core/src/session/manager.rs

@@ -1,7 +1,7 @@
 use std::collections::HashMap;
 use std::sync::Arc;
 
-use core_api::user_fs::UserFs;
+use core_api::user_fs::{SharedFs, UserFs};
 
 use sqlx::SqlitePool;
 use tokio::sync::Mutex;
@@ -29,8 +29,9 @@ pub struct ChatSessionManager {
     shared_pool:           Arc<SqlitePool>,
     user_id:               String,
     /// The owner's filesystem view, threaded to each handler and on into every
-    /// `ToolContext` (blueprint §6).
-    user_fs:               Arc<UserFs>,
+    /// `ToolContext` (blueprint §6). A shared swappable cell so a shared-folder
+    /// membership change ([`refresh_fs`](Self::refresh_fs)) reaches live sessions.
+    user_fs:               SharedFs,
     llm_manager:           Arc<LlmManager>,
     max_history_messages:  usize,
     max_tool_rounds:       usize,
@@ -60,7 +61,7 @@ impl ChatSessionManager {
         db:                    Arc<SqlitePool>,
         shared_pool:           Arc<SqlitePool>,
         user_id:               String,
-        user_fs:               Arc<UserFs>,
+        user_fs:               SharedFs,
         llm_manager:           Arc<LlmManager>,
         max_history_messages:  usize,
         max_tool_rounds:       usize,
@@ -171,7 +172,7 @@ impl ChatSessionManager {
             self.db.clone(),
             self.shared_pool.clone(),
             self.user_id.clone(),
-            Arc::clone(&self.user_fs),
+            self.user_fs.clone(),
             Arc::clone(&self.llm_manager),
             self.max_history_messages,
             self.max_tool_rounds,
@@ -197,4 +198,12 @@ impl ChatSessionManager {
         self.active.lock().await.insert(session_id, handler.clone());
         Ok(handler)
     }
+
+    /// Swaps in a refreshed filesystem view for this owner (blueprint §6 remount).
+    /// Every live session's handler shares the same [`SharedFs`] cell, so the new
+    /// membership reaches each on its next tool call — no handler eviction, no
+    /// cross-session race.
+    pub fn refresh_fs(&self, fs: UserFs) {
+        self.user_fs.store(fs);
+    }
 }