swarm ui: a stored claude login closes the dialog and shows a toast

The login dialog stayed open with a success line after the code was
accepted, though nothing is left to do in it. It now closes and a toast
says the login is stored. The toast is a new swarm-ui primitive: a short
note raised with showToast, rendered by a ToastHost at the app root, gone
after a few seconds or on click.

frontend/packages/swarm-ui/src/App.tsx

@@ -16,6 +16,7 @@ import { JobsPage } from "./pages/JobsPage.js";
 import { ReportsPage } from "./pages/reports/ReportsPage.js";
 import { StartPage } from "./pages/StartPage.js";
 import { Panel } from "./ui/panel/Panel.js";
+import { ToastHost } from "./ui/toast/Toast.js";
 
 // An address from before the tabs were folded together: replace it with the
 // tab that holds the page now, query kept.
@@ -34,6 +35,7 @@ function NotFound() {
 export function App() {
   return (
     <Router hook={useGuardedLocation}>
+      <ToastHost />
       <Shell>
         <Switch>
           <Route path="/" component={StartPage} />

frontend/packages/swarm-ui/src/agent/claude-login/ClaudeLoginDialog.css

@@ -1,4 +0,0 @@
-/* <ClaudeLoginDialog> */
-.claude-login-ok {
-  margin-block: 1em;
-}

frontend/packages/swarm-ui/src/agent/claude-login/ClaudeLoginDialog.tsx

@@ -13,8 +13,8 @@ import { Button } from "../../ui/button/Button.js";
 import { FormStack } from "../../ui/form-stack/FormStack.js";
 import { Dialog } from "../../ui/dialog/Dialog.js";
 import { ExternalLink } from "../../ui/external-link/ExternalLink.js";
-import { Hint } from "../../ui/hint/Hint.js";
 import { Panel } from "../../ui/panel/Panel.js";
+import { showToast } from "../../ui/toast/toasts.js";
 import { TextField } from "../../ui/text-field/TextField.js";
 import {
   afterCode,
@@ -25,9 +25,9 @@ import {
   leavesLoginRunning,
   pastedCode,
   startOutlivedDialog,
+  storedMessage,
   type LoginStep,
 } from "./ClaudeLoginSteps.js";
-import "./ClaudeLoginDialog.css";
 
 async function problemOf(r: Response): Promise<ProblemDetails | null> {
   return r.ok ? null : await readApiError(r);
@@ -80,16 +80,24 @@ export function ClaudeLoginDialog({
     if (step.step !== "code" || pasted === null) return;
     const { url } = step;
     setStep({ step: "submitting", url });
+    let next: LoginStep;
     try {
       const r = await fetch(claudeLoginPath(agent, true), {
         method: "POST",
         headers: { "content-type": "application/json" },
         body: JSON.stringify({ code: pasted }),
       });
-      setStep(afterCode(await problemOf(r)));
+      next = afterCode(await problemOf(r));
     } catch (err) {
-      setStep(afterCode({ detail: String(err) }));
+      next = afterCode({ detail: String(err) });
     }
+    if (next.step === "stored") {
+      // Nothing is left to do in the dialog: close it and say so in a toast.
+      onClose();
+      showToast(storedMessage(agent), "ok");
+      return;
+    }
+    setStep(next);
     setCode("");
   }
 
@@ -122,12 +130,6 @@ export function ClaudeLoginDialog({
             </FormStack>
           </>
         )}
-        {step.step === "stored" && (
-          <Hint tone="ok" class="claude-login-ok">
-            Stored. <strong>{agent}</strong> picks the login up within a minute
-            and resumes.
-          </Hint>
-        )}
         {step.step === "failed" && (
           <ApiErrorPanel
             context="the claude login failed; close and start again"

frontend/packages/swarm-ui/src/agent/claude-login/ClaudeLoginSteps.ts

@@ -28,6 +28,11 @@ export function afterCode(problem: ProblemDetails | null): LoginStep {
   return problem === null ? { step: "stored" } : { step: "failed", problem };
 }
 
+// What the toast says once the login is stored.
+export function storedMessage(agent: string): string {
+  return `Login stored. ${agent} picks it up within a minute and resumes.`;
+}
+
 // Whether closing the dialog leaves a login running that should be
 // stopped.
 export function leavesLoginRunning(s: LoginStep): boolean {

frontend/packages/swarm-ui/src/ui/toast/Toast.css

@@ -0,0 +1,37 @@
+/* <ToastHost>: a fixed stack top-right above the page. The host takes no
+   clicks itself, so it never blocks the page below it; each toast does. A
+   toast raised while a modal dialog is open sits behind the dialog's top
+   layer, so raise one after closing the dialog. */
+.ui-toast-host {
+  position: fixed;
+  top: 1em;
+  right: 1em;
+  z-index: 1100;
+  display: flex;
+  flex-direction: column;
+  gap: 0.5em;
+  max-width: min(28em, 92vw);
+  pointer-events: none;
+}
+.ui-toast {
+  pointer-events: auto;
+  cursor: pointer;
+  background: var(--bg-elev);
+  border: 1px solid var(--border);
+  border-left-width: 3px;
+  border-radius: 0.4em;
+  box-shadow: 0 4px 20px -6px var(--crust);
+  padding: 0.6em 0.9em;
+  font-size: 0.9em;
+  color: var(--fg);
+  white-space: pre-wrap;
+}
+.ui-toast-info {
+  border-left-color: var(--purple-dim);
+}
+.ui-toast-ok {
+  border-left-color: var(--green);
+}
+.ui-toast-error {
+  border-left-color: var(--red);
+}

frontend/packages/swarm-ui/src/ui/toast/Toast.tsx

@@ -0,0 +1,43 @@
+// <ToastHost> — renders the toasts `showToast` raised, stacked top-right
+// above the page. Mounted once, at the app root. A toast removes itself after
+// its duration; a click dismisses it sooner. An error is announced as an
+// alert, the others as a status.
+import { useEffect, useState } from "preact/hooks";
+import {
+  currentToasts,
+  dismissToast,
+  subscribeToasts,
+  type Toast,
+} from "./toasts.js";
+import "./Toast.css";
+
+function ToastItem({ toast }: { toast: Toast }) {
+  useEffect(() => {
+    const timer = setTimeout(() => dismissToast(toast.id), toast.duration);
+    return () => clearTimeout(timer);
+  }, [toast.id, toast.duration]);
+  return (
+    <div
+      class={`ui-toast ui-toast-${toast.tone}`}
+      role={toast.tone === "error" ? "alert" : "status"}
+      onClick={() => dismissToast(toast.id)}
+    >
+      {toast.message}
+    </div>
+  );
+}
+
+export function ToastHost() {
+  const [list, setList] = useState<readonly Toast[]>(currentToasts());
+  useEffect(() => {
+    setList(currentToasts());
+    return subscribeToasts(() => setList(currentToasts()));
+  }, []);
+  return (
+    <div class="ui-toast-host">
+      {list.map((t) => (
+        <ToastItem key={t.id} toast={t} />
+      ))}
+    </div>
+  );
+}

frontend/packages/swarm-ui/src/ui/toast/toasts.ts

@@ -0,0 +1,59 @@
+// The toast list, kept out of the component so `npm test` runs it. A toast is
+// a short note that needs no answer: it shows for a few seconds and goes away
+// by itself, and a click dismisses it sooner. Anything that shows one calls
+// `showToast`; `<ToastHost>` renders the list.
+
+export type ToastTone = "info" | "ok" | "error";
+
+export interface Toast {
+  id: number;
+  message: string;
+  tone: ToastTone;
+  /** How long it stays, in ms. */
+  duration: number;
+}
+
+/** An error lingers longer, since it is the one worth reading twice. */
+export function toastDuration(tone: ToastTone): number {
+  return tone === "error" ? 8000 : 4000;
+}
+
+let toasts: Toast[] = [];
+let nextId = 1;
+const listeners = new Set<() => void>();
+
+function emit(): void {
+  for (const l of listeners) l();
+}
+
+/** Shows a toast and returns its id. */
+export function showToast(
+  message: string,
+  tone: ToastTone = "info",
+  duration: number = toastDuration(tone),
+): number {
+  const id = nextId++;
+  toasts = [...toasts, { id, message, tone, duration }];
+  emit();
+  return id;
+}
+
+/** Removes a toast; an id that is gone already does nothing. */
+export function dismissToast(id: number): void {
+  if (!toasts.some((t) => t.id === id)) return;
+  toasts = toasts.filter((t) => t.id !== id);
+  emit();
+}
+
+/** The toasts on screen, oldest first. */
+export function currentToasts(): readonly Toast[] {
+  return toasts;
+}
+
+/** Calls `fn` on every change; returns the function that stops it. */
+export function subscribeToasts(fn: () => void): () => void {
+  listeners.add(fn);
+  return () => {
+    listeners.delete(fn);
+  };
+}