fix(.gitignore): anchor Python build artifacts; recover panel/src/lib (28 files)

The 'lib/' rule (intended for Python virtualenv at repo root) was matching panel/src/lib/, hiding the entire panel API client + utility tree from git. Anchored Python build-artifact rules to the repo root with a leading slash so they only match at the top level. Adds 28 panel/src/lib files that should have been tracked from day one.

panel/src/lib/api/groups.ts

@@ -0,0 +1,61 @@
+/**
+ * Groups API Client
+ *
+ * API functions for group management within channels.
+ */
+
+import api from "./client";
+import { isMockMode } from "@/lib/mock-data";
+import type { Group } from "@/types";
+
+// =============================================================================
+// Types
+// =============================================================================
+
+export interface GroupCreate {
+  channel_id: string;
+  name: string;
+  hierarchy_level?: number;
+}
+
+// =============================================================================
+// API Client
+// =============================================================================
+
+export const groupsApi = {
+  /**
+   * Create a new group within a channel
+   */
+  create: async (group: GroupCreate): Promise<Group> => {
+    if (isMockMode()) {
+      return {
+        id: `group-${Date.now()}`,
+        name: group.name,
+        hierarchy_level: group.hierarchy_level ?? 0,
+        is_active: true,
+        total_messages: 0,
+        active_session_id: null,
+      };
+    }
+    const { data } = await api.post<Group>("/groups", group);
+    return data;
+  },
+
+  /**
+   * Get a group by ID
+   */
+  get: async (groupId: string): Promise<Group> => {
+    if (isMockMode()) {
+      return {
+        id: groupId,
+        name: "Mock Group",
+        hierarchy_level: 0,
+        is_active: true,
+        total_messages: 0,
+        active_session_id: null,
+      };
+    }
+    const { data } = await api.get<Group>(`/groups/${groupId}`);
+    return data;
+  },
+};