PAP-56: IA Phase 1 — left-nav restructure

Rebuild the sidebar to the board-locked IA structure (frontend-only):

- Add Conference room top-level item above New Task (chat-bubble icon),
  routing to a new placeholder page.
- Rename "New Issue" -> "New Task" and switch its label to the standard
  nav color (text-foreground/80) to match SidebarNavItem.
- Add Artifacts (new placeholder page) and Projects (-> existing /projects)
  to the Work section in the order Tasks · Routines · Goals · Workspaces ·
  Artifacts · Projects.
- Remove the old collapsible per-project PROJECTS section (SidebarProjects)
  from the sidebar; tiles get rebuilt in a child issue.
- Add /conference-room and /artifacts routes in App.tsx.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

ui/src/components/Sidebar.test.tsx

@@ -82,10 +82,6 @@ vi.mock("./SidebarCompanyMenu", () => ({
   SidebarCompanyMenu: () => <div>Company menu</div>,
 }));
 
-vi.mock("./SidebarProjects", () => ({
-  SidebarProjects: () => null,
-}));
-
 vi.mock("./SidebarAgents", () => ({
   SidebarAgents: () => null,
 }));

ui/src/components/Sidebar.tsx

@@ -12,12 +12,14 @@ import {
   Repeat,
   GitBranch,
   Settings,
+  MessagesSquare,
+  Package,
+  FolderOpen,
 } from "lucide-react";
 import { useQuery } from "@tanstack/react-query";
 import { NavLink } from "@/lib/router";
 import { SidebarSection } from "./SidebarSection";
 import { SidebarNavItem } from "./SidebarNavItem";
-import { SidebarProjects } from "./SidebarProjects";
 import { SidebarAgents } from "./SidebarAgents";
 import { useDialogActions } from "../context/DialogContext";
 import { useCompany } from "../context/CompanyContext";
@@ -73,14 +75,15 @@ export function Sidebar() {
 
       <nav className="flex-1 min-h-0 overflow-y-auto scrollbar-auto-hide flex flex-col gap-4 pointer-coarse:gap-3 px-3 py-2">
         <div className="flex flex-col gap-0.5">
-          {/* New Issue button aligned with nav items */}
+          <SidebarNavItem to="/conference-room" label="Conference room" icon={MessagesSquare} />
+          {/* New Task button aligned with nav items */}
           <button
             onClick={() => openNewIssue()}
             data-slot="icon-button"
-            className="flex items-center gap-2.5 px-3 py-2 pointer-coarse:py-1.5 text-[13px] font-medium text-muted-foreground hover:bg-accent/50 hover:text-foreground transition-colors"
+            className="flex items-center gap-2.5 px-3 py-2 pointer-coarse:py-1.5 text-[13px] font-medium text-foreground/80 hover:bg-accent/50 hover:text-foreground transition-colors"
           >
             <SquarePen className="h-4 w-4 shrink-0" />
-            <span className="truncate">New Issue</span>
+            <span className="truncate">New Task</span>
           </button>
           <SidebarNavItem to="/dashboard" label="Dashboard" icon={LayoutDashboard} liveCount={liveRunCount} />
           <SidebarNavItem
@@ -100,6 +103,8 @@ export function Sidebar() {
           {showWorkspacesLink ? (
             <SidebarNavItem to="/workspaces" label="Workspaces" icon={GitBranch} />
           ) : null}
+          <SidebarNavItem to="/artifacts" label="Artifacts" icon={Package} />
+          <SidebarNavItem to="/projects" label="Projects" icon={FolderOpen} />
           <PluginSlotOutlet
             slotTypes={["sidebar"]}
             context={pluginContext}
@@ -115,8 +120,6 @@ export function Sidebar() {
           />
         </SidebarSection>
 
-        <SidebarProjects />
-
         <SidebarAgents />
 
         <SidebarSection label="Company">