refactor(web): restructure to feature-based architecture with zustand stores

- Remove tab system entirely (tab-store, tab-bar, tab-link)
- Split monolithic AuthContext into zustand auth + workspace stores
- Move issue components/config to features/issues/
- Move WebSocket provider to features/realtime/
- Move api.ts to shared/
- Migrate all consumers from useAuth() to direct store imports
- Simplify sidebar: replace hand-built dropdown with shadcn DropdownMenu,
  replace custom layout wrapper with SidebarInset
- Remove unused @multica/store and @multica/hooks dependencies
- Add @/ path alias and zustand dependency
- Update CLAUDE.md with feature-based architecture conventions

Net change: +293 / -2435 lines

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/web/features/workspace/hooks.ts

@@ -0,0 +1,36 @@
+"use client";
+
+import { useWorkspaceStore } from "./store";
+
+export function useActorName() {
+  const members = useWorkspaceStore((s) => s.members);
+  const agents = useWorkspaceStore((s) => s.agents);
+
+  const getMemberName = (userId: string) => {
+    const m = members.find((m) => m.user_id === userId);
+    return m?.name ?? "Unknown";
+  };
+
+  const getAgentName = (agentId: string) => {
+    const a = agents.find((a) => a.id === agentId);
+    return a?.name ?? "Unknown Agent";
+  };
+
+  const getActorName = (type: string, id: string) => {
+    if (type === "member") return getMemberName(id);
+    if (type === "agent") return getAgentName(id);
+    return "System";
+  };
+
+  const getActorInitials = (type: string, id: string) => {
+    const name = getActorName(type, id);
+    return name
+      .split(" ")
+      .map((w) => w[0])
+      .join("")
+      .toUpperCase()
+      .slice(0, 2);
+  };
+
+  return { getMemberName, getAgentName, getActorName, getActorInitials };
+}

apps/web/features/workspace/index.ts

@@ -0,0 +1,2 @@
+export { useWorkspaceStore } from "./store";
+export { useActorName } from "./hooks";

apps/web/features/workspace/store.ts

@@ -0,0 +1,142 @@
+"use client";
+
+import { create } from "zustand";
+import type { Workspace, MemberWithUser, Agent } from "@multica/types";
+import { api } from "@/shared/api";
+
+interface WorkspaceState {
+  workspace: Workspace | null;
+  workspaces: Workspace[];
+  members: MemberWithUser[];
+  agents: Agent[];
+}
+
+interface WorkspaceActions {
+  hydrateWorkspace: (
+    wsList: Workspace[],
+    preferredWorkspaceId?: string | null,
+  ) => Promise<Workspace | null>;
+  switchWorkspace: (workspaceId: string) => Promise<void>;
+  refreshWorkspaces: () => Promise<Workspace[]>;
+  refreshMembers: () => Promise<void>;
+  refreshAgents: () => Promise<void>;
+  createWorkspace: (data: {
+    name: string;
+    slug: string;
+    description?: string;
+  }) => Promise<Workspace>;
+  updateWorkspace: (ws: Workspace) => void;
+  leaveWorkspace: (workspaceId: string) => Promise<void>;
+  deleteWorkspace: (workspaceId: string) => Promise<void>;
+  clearWorkspace: () => void;
+}
+
+type WorkspaceStore = WorkspaceState & WorkspaceActions;
+
+export const useWorkspaceStore = create<WorkspaceStore>((set, get) => ({
+  // State
+  workspace: null,
+  workspaces: [],
+  members: [],
+  agents: [],
+
+  // Actions
+  hydrateWorkspace: async (wsList, preferredWorkspaceId) => {
+    set({ workspaces: wsList });
+
+    const nextWorkspace =
+      (preferredWorkspaceId
+        ? wsList.find((item) => item.id === preferredWorkspaceId)
+        : null) ??
+      wsList[0] ??
+      null;
+
+    if (!nextWorkspace) {
+      api.setWorkspaceId(null);
+      localStorage.removeItem("multica_workspace_id");
+      set({ workspace: null, members: [], agents: [] });
+      return null;
+    }
+
+    api.setWorkspaceId(nextWorkspace.id);
+    localStorage.setItem("multica_workspace_id", nextWorkspace.id);
+    set({ workspace: nextWorkspace });
+
+    const [nextMembers, nextAgents] = await Promise.all([
+      api.listMembers(nextWorkspace.id),
+      api.listAgents({ workspace_id: nextWorkspace.id }),
+    ]);
+    set({ members: nextMembers, agents: nextAgents });
+
+    return nextWorkspace;
+  },
+
+  switchWorkspace: async (workspaceId) => {
+    const { workspaces, hydrateWorkspace } = get();
+    const ws = workspaces.find((item) => item.id === workspaceId);
+    if (!ws) return;
+
+    await hydrateWorkspace(workspaces, ws.id);
+  },
+
+  refreshWorkspaces: async () => {
+    const { workspace, hydrateWorkspace } = get();
+    const storedWorkspaceId = localStorage.getItem("multica_workspace_id");
+    const wsList = await api.listWorkspaces();
+    await hydrateWorkspace(wsList, workspace?.id ?? storedWorkspaceId);
+    return wsList;
+  },
+
+  refreshMembers: async () => {
+    const { workspace } = get();
+    if (!workspace) return;
+    const members = await api.listMembers(workspace.id);
+    set({ members });
+  },
+
+  refreshAgents: async () => {
+    const { workspace } = get();
+    if (!workspace) return;
+    const agents = await api.listAgents({ workspace_id: workspace.id });
+    set({ agents });
+  },
+
+  createWorkspace: async (data) => {
+    const ws = await api.createWorkspace(data);
+    set((state) => ({ workspaces: [...state.workspaces, ws] }));
+    return ws;
+  },
+
+  updateWorkspace: (ws) => {
+    set((state) => ({
+      workspace: state.workspace?.id === ws.id ? ws : state.workspace,
+      workspaces: state.workspaces.map((item) =>
+        item.id === ws.id ? ws : item,
+      ),
+    }));
+  },
+
+  leaveWorkspace: async (workspaceId) => {
+    await api.leaveWorkspace(workspaceId);
+    const { workspace, hydrateWorkspace } = get();
+    const wsList = await api.listWorkspaces();
+    const preferredWorkspaceId =
+      workspace?.id === workspaceId ? null : (workspace?.id ?? null);
+    await hydrateWorkspace(wsList, preferredWorkspaceId);
+  },
+
+  deleteWorkspace: async (workspaceId) => {
+    await api.deleteWorkspace(workspaceId);
+    const { workspace, hydrateWorkspace } = get();
+    const wsList = await api.listWorkspaces();
+    const preferredWorkspaceId =
+      workspace?.id === workspaceId ? null : (workspace?.id ?? null);
+    await hydrateWorkspace(wsList, preferredWorkspaceId);
+  },
+
+  clearWorkspace: () => {
+    api.setWorkspaceId(null);
+    localStorage.removeItem("multica_workspace_id");
+    set({ workspace: null, workspaces: [], members: [], agents: [] });
+  },
+}));