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/db/shared_folders.rs

@@ -15,6 +15,9 @@ use sqlx::SqlitePool;
 pub struct SharedFolder {
     pub id:          i64,
     pub folder_name: String,
+    /// What the folder holds — injected into the agent's system context so it
+    /// knows what to store here and when to read it. Admin-authored (§6).
+    pub description: String,
     pub created_at:  String,
 }
 
@@ -59,25 +62,50 @@ pub async fn list_for_user(pool: &SqlitePool, user_id: &str) -> Result<Vec<Share
 }
 
 pub async fn list_all(pool: &SqlitePool) -> Result<Vec<SharedFolder>> {
-    let rows = sqlx::query_as::<_, (i64, String, String)>(
-        "SELECT id, folder_name, created_at FROM shared_folders ORDER BY folder_name",
+    let rows = sqlx::query_as::<_, (i64, String, String, String)>(
+        "SELECT id, folder_name, description, created_at FROM shared_folders ORDER BY folder_name",
     )
     .fetch_all(pool)
     .await?;
     Ok(rows
         .into_iter()
-        .map(|(id, folder_name, created_at)| SharedFolder { id, folder_name, created_at })
+        .map(|(id, folder_name, description, created_at)| SharedFolder {
+            id,
+            folder_name,
+            description,
+            created_at,
+        })
         .collect())
 }
 
+pub async fn get(pool: &SqlitePool, folder_id: i64) -> Result<Option<SharedFolder>> {
+    let row = sqlx::query_as::<_, (i64, String, String, String)>(
+        "SELECT id, folder_name, description, created_at FROM shared_folders WHERE id = ?",
+    )
+    .bind(folder_id)
+    .fetch_optional(pool)
+    .await?;
+    Ok(row.map(|(id, folder_name, description, created_at)| SharedFolder {
+        id,
+        folder_name,
+        description,
+        created_at,
+    }))
+}
+
 pub async fn get_by_name(pool: &SqlitePool, folder_name: &str) -> Result<Option<SharedFolder>> {
-    let row = sqlx::query_as::<_, (i64, String, String)>(
-        "SELECT id, folder_name, created_at FROM shared_folders WHERE folder_name = ?",
+    let row = sqlx::query_as::<_, (i64, String, String, String)>(
+        "SELECT id, folder_name, description, created_at FROM shared_folders WHERE folder_name = ?",
     )
     .bind(folder_name)
     .fetch_optional(pool)
     .await?;
-    Ok(row.map(|(id, folder_name, created_at)| SharedFolder { id, folder_name, created_at }))
+    Ok(row.map(|(id, folder_name, description, created_at)| SharedFolder {
+        id,
+        folder_name,
+        description,
+        created_at,
+    }))
 }
 
 /// The members of a folder — the set of users whose containers mount it.
@@ -98,15 +126,27 @@ pub async fn members(pool: &SqlitePool, folder_id: i64) -> Result<Vec<FolderMemb
 
 /// Creates a folder, returning its id. `folder_name` must already be validated as
 /// a safe path component (see [`is_valid_folder_name`]).
-pub async fn create(pool: &SqlitePool, folder_name: &str) -> Result<i64> {
-    let id = sqlx::query("INSERT INTO shared_folders (folder_name) VALUES (?)")
+pub async fn create(pool: &SqlitePool, folder_name: &str, description: &str) -> Result<i64> {
+    let id = sqlx::query("INSERT INTO shared_folders (folder_name, description) VALUES (?, ?)")
         .bind(folder_name)
+        .bind(description)
         .execute(pool)
         .await?
         .last_insert_rowid();
     Ok(id)
 }
 
+/// Updates a folder's description — the agent-facing text. No-op if `folder_id`
+/// no longer exists.
+pub async fn set_description(pool: &SqlitePool, folder_id: i64, description: &str) -> Result<()> {
+    sqlx::query("UPDATE shared_folders SET description = ? WHERE id = ?")
+        .bind(description)
+        .bind(folder_id)
+        .execute(pool)
+        .await?;
+    Ok(())
+}
+
 /// Adds (or updates the capability of) a member. Idempotent on the PK.
 pub async fn add_member(
     pool:      &SqlitePool,