feat(pet): cleared alerts stay cleared, contextual bubbles, i18n, moments, chat window

- Fix: an errored session alerted on every update, and Clear alerts only
  dropped it in memory, so its next update (or a reload) brought the alert
  straight back. An error now alerts on the transition into error only;
  cleared sessions are remembered (agenthub.pet.dismissedErrors) and stay
  quiet until they recover and fail anew.
- Quips, greetings, notifications and Ask answers move to i18n (EN/VI);
  Ask understands Vietnamese keywords and names the sessions it counts.
- The pet goes by the worn pet's name; click it in the panel to rename
  (agenthub.pet.names, synced to the account).
- Bubbles name the session they are about, with an Open button (never a
  resume); a burst of the same event coalesces into one count.
- Moments: a new session waves, a finish hops, a subagent peeks, a wait taps,
  an error flinches — on Sagi, Codex sprites and still images. Idle fidgets,
  a once-per-session greeting, a "Needs you" list, an amber waiting dot.
- Pat (heart button, Ask, or stroking the pet) reacts on the pet itself, so
  it shows while the panel or chat is open.
- Panel drops Run Claude / Activity / Sessions / Errored.
- Ask hands off to a chat window (PetChat) on the default AI tool
  (Claude/Codex): transcript as bubbles, follow-ups and CLI menus through an
  off-screen attached terminal; no new server route.

Verified on HEAD + this diff in a clean worktree: tsc -b, the full client
suite (1334/1335; the one failure, ConversationView.follow, is flaky under
load and passes 3/3 alone) and server me-prefs.test.js.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

client/src/components/Sagi/SpeechBubble.tsx

@@ -1,14 +1,14 @@
 /**
  * @file SpeechBubble.tsx
  * @description Transient speech bubble rendered above the Sagi mascot.
- * Pure presentation — visibility timing and quip selection live in
- * {@link useSagiBrain}; this component only paints the bubble and handles
- * user dismissal.
+ * Pure presentation — visibility timing, coalescing and quip selection live in
+ * {@link useSagiBrain}; this component paints the line, the session(s) it is
+ * about, an Open button when it is about exactly one, and handles dismissal.
  *
  * ## Accessibility
  * Uses `role="status"` with `aria-live="polite"` so screen readers announce
- * new quips without interrupting current speech. Click anywhere on the bubble
- * to dismiss early.
+ * new quips without interrupting current speech. Click the bubble to dismiss
+ * it early; its Open button opens the session instead.
  *
  * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
  */
@@ -52,30 +52,52 @@
  * ----------------------------------------------------------------------------- */
 
 import { useTranslation } from "react-i18next";
+import type { SagiBubble } from "./useSagiBrain";
+import type { SagiSubject } from "./brain";
 
 /** Props for {@link SpeechBubble}. */
 interface SpeechBubbleProps {
-  /** Quip text to display inside the bubble. */
-  text: string;
+  bubble: SagiBubble;
   /** Called when the user clicks to dismiss. */
   onDismiss: () => void;
+  /** Opens the session the bubble is about. */
+  onOpen?: (subject: SagiSubject) => void;
 }
 
 /**
  * Animated speech bubble above Sagi.
  * @param props See {@link SpeechBubbleProps}.
  */
-export function SpeechBubble({ text, onDismiss }: SpeechBubbleProps) {
+export function SpeechBubble({ bubble, onDismiss, onOpen }: SpeechBubbleProps) {
   const { t } = useTranslation("settings");
+  const { text, detail, subject, tone } = bubble;
   return (
     <div
       className="sagi-bubble sagi-bubble-enter"
+      data-tone={tone}
       role="status"
       aria-live="polite"
       onClick={onDismiss}
       title={t("sagi.bubbleDismiss")}
     >
-      {text}
+      <div>{text}</div>
+      {(detail || (subject && onOpen)) && (
+        <div className="sagi-bubble-detail">
+          {detail && <span className="sagi-bubble-subject">{detail}</span>}
+          {subject && onOpen && (
+            <button
+              type="button"
+              className="sagi-bubble-open"
+              onClick={(e) => {
+                e.stopPropagation();
+                onOpen(subject);
+              }}
+            >
+              {t("sagi.bubbleOpen")}
+            </button>
+          )}
+        </div>
+      )}
     </div>
   );
 }