Make a workspace page a dashboard and drop its coordinator from the rail

The workspace rail now lists only the bots attached to the workspace, with the back link returning to the workspace page from a bot's conversation. /admin/workspaces/<id> becomes a read-only dashboard (picture, context, latest activity, bots, computers) that links into the editable settings page.

src/types/index.ts

@@ -82,6 +82,19 @@ export type WorkspaceWithActivity = BUN_SQLITE_COBBLE_WORKSPACES & {
     last_activity_at?: number | null;
 };
 
+/**
+ * One recent conversation in a workspace, for its dashboard: the user's
+ * session with the bot, and the bot it's with.
+ */
+export type WorkspaceActivityItem = BUN_SQLITE_COBBLE_BOT_SESSIONS & {
+    message_count: number;
+    last_message_text?: string | null;
+    bot_name?: string | null;
+    bot_image_media_id?: number | null;
+    bot_hue?: string | null;
+    bot_face?: string | null;
+};
+
 /**
  * A computer with its container's state, for lists and the Add flow.
  */
@@ -392,6 +405,10 @@ export type PagePropsType = {
     all_bots?: BotWithLastMessage[] | null;
     workspace_computers?: ComputerWithStatus[] | null;
     computers?: ComputerWithStatus[] | null;
+    /**
+     * A workspace's dashboard: the user's latest sessions there.
+     */
+    workspace_activity?: WorkspaceActivityItem[] | null;
     /**
      * The computer a settings page manages, with its access.
      */