Grow the companion, fix idle fallback, add update banner

Companion: bump the corner mascot ~12% (128→144) and make animation
resolution robust — fall back to the idle clip when a mood has no clip of
its own, and pin the always-asleep cat to one pose so its Lottie never
reloads. This stops a bare emoji from replacing the cute companion on idle.

Update notifications: serve a build id at /api/version (a hash of the
embedded dist/index.html, which changes on every frontend deploy). The
client records its load-time id, polls every 90s (and on tab focus), and
floats a Mandarin-first "new version available" banner offering a refresh
when the id changes.

Claude-Session: https://claude.ai/code/session_016Yr6jELuRc7hyzYLccQKZd

cmd/server/main.go

@@ -1,6 +1,8 @@
 package main
 
 import (
+	"crypto/sha256"
+	"encoding/hex"
 	"errors"
 	"io/fs"
 	"log"
@@ -34,12 +36,26 @@ func main() {
 	r.Use(middleware.Logger)
 	r.Use(middleware.Recoverer)
 
+	// Build version: a hash of the embedded SPA shell. Vite rewrites index.html
+	// with content-hashed asset names on every build, so this string changes
+	// exactly when a new frontend is deployed — the client polls it to know when
+	// to offer a refresh.
+	version := buildVersion()
+	log.Printf("frontend build version %s", version)
+
 	r.Route("/api", func(api chi.Router) {
 		api.Get("/health", func(w http.ResponseWriter, _ *http.Request) {
 			w.Header().Set("Content-Type", "application/json")
 			_, _ = w.Write([]byte(`{"status":"ok"}`))
 		})
 
+		api.Get("/version", func(w http.ResponseWriter, _ *http.Request) {
+			w.Header().Set("Content-Type", "application/json")
+			// Never cache: a stale cached version would defeat the whole check.
+			w.Header().Set("Cache-Control", "no-store")
+			_, _ = w.Write([]byte(`{"version":"` + version + `"}`))
+		})
+
 		llmClient := llm.NewLLMClient(cfg)
 		sug := suggestions.New(database, llmClient)
 
@@ -63,6 +79,19 @@ func main() {
 	}
 }
 
+// buildVersion derives a short, stable identifier for the currently embedded
+// frontend by hashing dist/index.html. Vite stamps content-hashed asset names
+// into that file each build, so the digest is a reliable "did the deploy
+// change?" signal. Falls back to "dev" when the frontend hasn't been built.
+func buildVersion() string {
+	data, err := fs.ReadFile(web.DistFS, "dist/index.html")
+	if err != nil {
+		return "dev"
+	}
+	sum := sha256.Sum256(data)
+	return hex.EncodeToString(sum[:])[:12]
+}
+
 // spaHandler serves the embedded web/dist as a single-page app: static files
 // when they exist, falling back to index.html for unknown paths. If the
 // frontend hasn't been built yet, it returns a friendly dev hint instead.

web/src/App.tsx

@@ -7,8 +7,11 @@ import { DocList } from './components/DocList/DocList'
 import { EditorCore, type EditorChange } from './components/Editor/EditorCore'
 import { StatusBar } from './components/StatusBar/StatusBar'
 import { PetalCompanion } from './components/Companion/PetalCompanion'
+import { UpdateBanner } from './components/UpdateBanner/UpdateBanner'
+import { useVersionWatch } from './hooks/useVersionWatch'
 
 export default function App() {
+  const updateAvailable = useVersionWatch()
   const [docs, setDocs] = useState<DocSummary[]>([])
   const [currentDoc, setCurrentDoc] = useState<Document | null>(null)
   const [title, setTitle] = useState('')
@@ -250,6 +253,8 @@ export default function App() {
         </main>
       </div>
 
+      {updateAvailable && <UpdateBanner />}
+
       <PetalCompanion
         wordCount={wordCount}
         saveStatus={status}

web/src/api/client.ts

@@ -82,6 +82,10 @@ export const api = {
     req<void>(`/suggestions/${id}/accept`, { method: 'POST' }),
   dismissSuggestion: (id: string) =>
     req<void>(`/suggestions/${id}/dismiss`, { method: 'POST' }),
+
+  // Current deployed build id — changes whenever a new frontend ships. The
+  // app polls this to offer a refresh. Bypasses any cache so the answer is live.
+  version: () => req<{ version: string }>('/version', { cache: 'no-store' }),
 }
 
 // One turn in an Ask Petal conversation. History lives only in the component —

web/src/components/Companion/PetalCompanion.tsx

@@ -44,10 +44,20 @@ export function PetalCompanion({ wordCount, saveStatus, editTick, acceptTick }:
   // dozes them, keep their normal idle pose instead of a sleepy face. Only a
   // mascot with a real sleep animation (the always-asleep cat) shows the zzz.
   const hasSleepClip = Boolean(companion.animations.sleeping)
-  const renderMood: Mood =
-    mood === 'sleeping' && !companion.alwaysAsleep && !hasSleepClip ? 'idle' : mood
+  // An always-asleep mascot (the cat) stays pinned to one pose so its Lottie
+  // never reloads as the engine flips moods underneath it.
+  const renderMood: Mood = companion.alwaysAsleep
+    ? 'idle'
+    : mood === 'sleeping' && !hasSleepClip
+      ? 'idle'
+      : mood
   const napping = companion.alwaysAsleep || (mood === 'sleeping' && hasSleepClip)
 
+  // Never swap the cute companion for a bare emoji on an idle nap: fall back to
+  // the idle animation when a mood has no clip of its own, and only reach for
+  // the emoji if the companion ships no animations at all.
+  const animationData = companion.animations[renderMood] ?? companion.animations.idle
+
   function choose(id: string) {
     setCompanionId(id)
     try {
@@ -153,8 +163,8 @@ export function PetalCompanion({ wordCount, saveStatus, editTick, acceptTick }:
         aria-label="Choose a companion"
         className={`petal-companion pointer-events-auto select-none ${napping ? 'petal-companion-sleep' : ''}`}
         style={{
-          width: 128,
-          height: 128,
+          width: 144,
+          height: 144,
           padding: 0,
           borderRadius: 'var(--radius-pill)',
           background: 'var(--color-surface-alt)',
@@ -167,9 +177,9 @@ export function PetalCompanion({ wordCount, saveStatus, editTick, acceptTick }:
       >
         <LottiePlayer
           key={companion.id}
-          animationData={companion.animations[renderMood]}
-          className="h-28 w-28"
-          fallback={<span style={{ fontSize: 64, lineHeight: 1 }}>{MOOD_EMOJI[renderMood]}</span>}
+          animationData={animationData}
+          className="h-32 w-32"
+          fallback={<span style={{ fontSize: 72, lineHeight: 1 }}>{MOOD_EMOJI[renderMood]}</span>}
         />
         {napping && (
           <span className="petal-zzz absolute" aria-hidden style={{ color: 'var(--color-muted)' }}>

web/src/components/UpdateBanner/UpdateBanner.tsx

@@ -0,0 +1,64 @@
+import { useState } from 'react'
+
+// UpdateBanner gently floats down from the top when a newer build has been
+// deployed, inviting a refresh. Mandarin-first copy (north star Note #17), soft
+// rose styling, and a clear primary action. Dismissable — if she dismisses it,
+// the next deploy (or reload) will surface a fresh one.
+export function UpdateBanner() {
+  const [dismissed, setDismissed] = useState(false)
+  if (dismissed) return null
+
+  return (
+    <div className="pointer-events-none fixed inset-x-0 top-4 z-50 flex justify-center px-4">
+      <div
+        role="status"
+        className="petal-update pointer-events-auto flex items-center gap-3 py-2.5 pl-4 pr-2.5"
+        style={{
+          background: 'var(--color-surface)',
+          border: '1px solid var(--color-border)',
+          borderRadius: 'var(--radius-pill)',
+          boxShadow: 'var(--shadow-soft)',
+          fontFamily: 'var(--font-ui)',
+          maxWidth: 'min(92vw, 460px)',
+        }}
+      >
+        <span aria-hidden style={{ fontSize: 20, lineHeight: 1 }}>
+          🌸
+        </span>
+        <div className="min-w-0">
+          <p
+            className="truncate text-sm font-bold leading-snug"
+            style={{ color: 'var(--color-plum)' }}
+          >
+            有新版本啦
+          </p>
+          <p className="truncate text-xs leading-snug" style={{ color: 'var(--color-muted)' }}>
+            A new version is ready — refresh to update.
+          </p>
+        </div>
+        <button
+          type="button"
+          onClick={() => window.location.reload()}
+          className="shrink-0 rounded-full px-3.5 py-1.5 text-sm font-bold text-white transition-colors"
+          style={{ background: 'var(--color-accent)' }}
+          onMouseEnter={(e) => (e.currentTarget.style.background = 'var(--color-accent-hover)')}
+          onMouseLeave={(e) => (e.currentTarget.style.background = 'var(--color-accent)')}
+        >
+          刷新 · Refresh
+        </button>
+        <button
+          type="button"
+          onClick={() => setDismissed(true)}
+          aria-label="稍后再说 · Dismiss"
+          title="稍后再说 · Dismiss"
+          className="shrink-0 rounded-full px-1.5 text-lg leading-none transition-colors"
+          style={{ color: 'var(--color-muted)' }}
+          onMouseEnter={(e) => (e.currentTarget.style.color = 'var(--color-plum)')}
+          onMouseLeave={(e) => (e.currentTarget.style.color = 'var(--color-muted)')}
+        >
+          ×
+        </button>
+      </div>
+    </div>
+  )
+}

web/src/hooks/useVersionWatch.ts

@@ -0,0 +1,52 @@
+import { useEffect, useRef, useState } from 'react'
+import { api } from '../api/client'
+
+// How often to ask the server whether a newer frontend has shipped. Gentle —
+// a deploy is rare, and the check is a tiny no-store GET.
+const POLL_MS = 90_000
+
+// useVersionWatch records the build id the app loaded with, then quietly polls
+// /api/version. When the server reports a different id, a new version has been
+// deployed and `updateAvailable` flips true (and stays true) so the UI can
+// offer a refresh. Network blips are ignored — it only ever reacts to a real,
+// confirmed change. Returns false until the baseline is established.
+export function useVersionWatch(): boolean {
+  const [updateAvailable, setUpdateAvailable] = useState(false)
+  // The version we're currently running. Null until the first successful fetch.
+  const baseline = useRef<string | null>(null)
+
+  useEffect(() => {
+    let active = true
+
+    const check = async () => {
+      try {
+        const { version } = await api.version()
+        if (!active || !version) return
+        if (baseline.current === null) {
+          baseline.current = version // first read: this is "us"
+        } else if (version !== baseline.current) {
+          setUpdateAvailable(true)
+        }
+      } catch {
+        /* offline / server bounce — try again next tick, never alarm the user */
+      }
+    }
+
+    check()
+    const id = setInterval(check, POLL_MS)
+    // Re-check the moment she returns to the tab, so a deploy that happened while
+    // she was away surfaces right away instead of up to POLL_MS later.
+    const onVisible = () => {
+      if (document.visibilityState === 'visible') check()
+    }
+    document.addEventListener('visibilitychange', onVisible)
+
+    return () => {
+      active = false
+      clearInterval(id)
+      document.removeEventListener('visibilitychange', onVisible)
+    }
+  }, [])
+
+  return updateAvailable
+}

web/src/index.css

@@ -239,6 +239,15 @@ button, a, input {
   100% { opacity: 0; transform: translateY(-14px) scale(1.1); }
 }
 
+/* "New version available" banner — drifts down from the top like a petal. */
+.petal-update {
+  animation: petal-drop 360ms cubic-bezier(0.2, 0.8, 0.3, 1.2) both;
+}
+@keyframes petal-drop {
+  from { opacity: 0; transform: translateY(-14px) scale(0.96); }
+  to   { opacity: 1; transform: translateY(0) scale(1); }
+}
+
 /* Blinking caret in the Ask Petal bubble while awaiting the first token. */
 .petal-chat-caret {
   animation: petal-breathe 1s ease-in-out infinite;