feat(app): settings modal — terminal, appearance, shell

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/src/App.tsx

@@ -5,6 +5,7 @@ import { TopBar } from "./TopBar";
 import { CenterToolbar } from "./CenterToolbar";
 import { Wizard } from "./Wizard";
 import { ConfirmDelete } from "./ConfirmDelete";
+import { Settings } from "./Settings";
 import { EventCenter } from "./EventCenter";
 import { maybeNotify } from "./notify";
 import { COLORS, applyTheme, resolvePalette } from "./theme";
@@ -31,6 +32,7 @@ export function App() {
   const [events, setEvents] = useState<EventRecord[]>([]);
   const [wizard, setWizard] = useState(false);
   const [deleteTarget, setDeleteTarget] = useState<WorkspaceView | null>(null);
+  const [settingsOpen, setSettingsOpen] = useState(false);
   const [eventsOpen, setEventsOpen] = useState(() => loadFlag("spacesh.eventsOpen", true));
   const [sidebarOpen, setSidebarOpen] = useState(() => loadFlag("spacesh.sidebarOpen", true));
   const [health, setHealth] = useState<DaemonHealth | null>(null);
@@ -147,7 +149,7 @@ export function App() {
 
   return (
     <div style={{ display: "flex", flexDirection: "column", height: "100vh", background: COLORS.bgApp }}>
-      <TopBar active={active} eventsOpen={eventsOpen} onToggleEvents={() => setEventsOpen((v) => !v)} onShowEvents={() => setEventsOpen(true)} sidebarOpen={sidebarOpen} onToggleSidebar={() => setSidebarOpen((v) => !v)} unread={unread} />
+      <TopBar active={active} eventsOpen={eventsOpen} onToggleEvents={() => setEventsOpen((v) => !v)} onShowEvents={() => setEventsOpen(true)} sidebarOpen={sidebarOpen} onToggleSidebar={() => setSidebarOpen((v) => !v)} unread={unread} onOpenSettings={() => setSettingsOpen(true)} />
       <div style={{ flex: 1, display: "flex", minHeight: 0 }}>
         {sidebarOpen && <Sidebar groups={groups} workspaces={workspaces} activeId={activeId} onSelect={selectWorkspace} onNew={() => setWizard(true)} onDelete={setDeleteTarget} health={health} connected={connected} />}
         <div style={{ flex: 1, display: "flex", flexDirection: "column", minWidth: 0 }}>
@@ -168,6 +170,7 @@ export function App() {
           />
         )}
       </div>
+      {settingsOpen && config && <Settings config={config} health={health} onClose={() => setSettingsOpen(false)} />}
       {wizard && <Wizard onDone={(id) => { setWizard(false); setActiveId(id); void refresh(); }} onCancel={() => setWizard(false)} />}
       {deleteTarget && (
         <ConfirmDelete