refactor(buddy): align companion system with official CLI

## Summary

Reverse-engineered the official Claude Code CLI (v2.1.91) buddy/companion
system and aligned our implementation to match.

## Changes (7 files)

### Added
- `src/buddy/CompanionCard.tsx` (+109)
  JSX bordered card matching official vc8: rarity header, colored sprite,
  name, personality, 10-bar stats, last reaction in nested border.

- `src/buddy/companionReact.ts` (+156)
  Reaction system matching official ZUK+Dc8: 45s rate limiting, @-mention
  detection, transcript builder (12 msgs, 5000 chars), POST buddy_react API.

### Modified
- `src/commands/buddy/index.ts`
  type: local -> local-jsx, description/argumentHint/immediate/isHidden.

- `src/commands/buddy/buddy.ts`
  LocalCommandCall -> LocalJSXCommandCall signature (onDone, context, args).
  Removed mute/unmute/rehatch (official uses off/on only).
  /buddy show returns CompanionCard JSX instead of plain text.
  Pet auto-unmutes. companionMuted writes globalConfig (matches UI read source).

- `src/screens/REPL.tsx` (line 2808)
  globalThis.fireCompanionObserver -> import triggerCompanionReaction.

- `src/state/AppStateStore.ts` — comment fix.
- `src/types/global.d.ts` — removed fireCompanionObserver declaration.

## Data flow (verified consistent)
- companionMuted: saveGlobalConfig() <-> getGlobalConfig() (6 read sites)
- companionReaction: setAppState() <-> useAppState() (4 sites)
- companionPetAt: setAppState() <-> useAppState() (2 sites)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/buddy/companionReact.ts

@@ -0,0 +1,156 @@
+/**
+ * Companion reaction system — aligns with official ZUK + Dc8 pattern.
+ *
+ * Called from REPL.tsx after each query turn. Checks mute state, frequency
+ * limits, and @-mention detection, then calls the buddy_react API to
+ * generate a reaction shown in the CompanionSprite speech bubble.
+ */
+import { getCompanion } from './companion.js'
+import { getGlobalConfig } from '../utils/config.js'
+import { getClaudeAIOAuthTokens } from '../utils/auth.js'
+import { getOauthConfig } from '../constants/oauth.js'
+import { getUserAgent } from '../utils/http.js'
+import type { Message } from '../types/message.js'
+
+// ─── Rate limiting ──────────────────────────────────
+
+let lastReactTime = 0
+const MIN_INTERVAL_MS = 45_000 // official is roughly 30-60s
+
+// ─── Recent reactions (avoid repetition) ────────────
+
+const recentReactions: string[] = []
+const MAX_RECENT = 8
+
+// ─── Public API ─────────────────────────────────────
+
+/**
+ * Trigger a companion reaction after a query turn.
+ *
+ * Mirrors official `ZUK()`:
+ *  1. Check companion exists and is not muted
+ *  2. Detect if user @-mentioned companion by name
+ *  3. Apply rate limiting (skip if not addressed and too soon)
+ *  4. Build conversation transcript
+ *  5. Call buddy_react API
+ *  6. Pass reaction text to setReaction callback
+ */
+export function triggerCompanionReaction(
+  messages: Message[],
+  setReaction: (text: string | undefined) => void,
+): void {
+  const companion = getCompanion()
+  if (!companion || getGlobalConfig().companionMuted) return
+
+  const addressed = isAddressed(messages, companion.name)
+
+  const now = Date.now()
+  if (!addressed && now - lastReactTime < MIN_INTERVAL_MS) return
+
+  const transcript = buildTranscript(messages)
+  if (!transcript.trim()) return
+
+  lastReactTime = now
+
+  void callBuddyReactAPI(companion, transcript, addressed)
+    .then(reaction => {
+      if (!reaction) return
+      recentReactions.push(reaction)
+      if (recentReactions.length > MAX_RECENT) recentReactions.shift()
+      setReaction(reaction)
+    })
+    .catch(() => {})
+}
+
+// ─── Helpers ────────────────────────────────────────
+
+function isAddressed(messages: Message[], name: string): boolean {
+  const pattern = new RegExp(`\\b${escapeRegex(name)}\\b`, 'i')
+  for (
+    let i = messages.length - 1;
+    i >= Math.max(0, messages.length - 3);
+    i--
+  ) {
+    const m = messages[i]
+    if (m?.type !== 'user') continue
+    const content = (m as any).message?.content
+    if (typeof content === 'string' && pattern.test(content)) return true
+  }
+  return false
+}
+
+function escapeRegex(s: string): string {
+  return s.replace(/[.*+?^${}()|[\]\\]/g, '\\$&')
+}
+
+function buildTranscript(messages: Message[]): string {
+  return messages
+    .slice(-12)
+    .filter(m => m.type === 'user' || m.type === 'assistant')
+    .map(m => {
+      const role = m.type === 'user' ? 'user' : 'claude'
+      const content = (m as any).message?.content
+      const text =
+        typeof content === 'string'
+          ? content.slice(0, 300)
+          : Array.isArray(content)
+            ? content
+                .filter((b: any) => b?.type === 'text')
+                .map((b: any) => b.text)
+                .join(' ')
+                .slice(0, 300)
+            : ''
+      return `${role}: ${text}`
+    })
+    .join('\n')
+    .slice(0, 5000)
+}
+
+// ─── API call ───────────────────────────────────────
+
+async function callBuddyReactAPI(
+  companion: {
+    name: string
+    personality: string
+    species: string
+    rarity: string
+    stats: Record<string, number>
+  },
+  transcript: string,
+  addressed: boolean,
+): Promise<string | null> {
+  const tokens = getClaudeAIOAuthTokens()
+  if (!tokens?.accessToken) return null
+
+  const orgId = getGlobalConfig().oauthAccount?.organizationUuid
+  if (!orgId) return null
+
+  const baseUrl = getOauthConfig().BASE_API_URL
+  const url = `${baseUrl}/api/organizations/${orgId}/claude_code/buddy_react`
+
+  const resp = await fetch(url, {
+    method: 'POST',
+    headers: {
+      Authorization: `Bearer ${tokens.accessToken}`,
+      'Content-Type': 'application/json',
+      'User-Agent': getUserAgent(),
+    },
+    body: JSON.stringify({
+      name: companion.name.slice(0, 32),
+      personality: companion.personality.slice(0, 200),
+      species: companion.species,
+      rarity: companion.rarity,
+      stats: companion.stats,
+      transcript,
+      reason: addressed ? 'addressed' : 'turn',
+      recent: recentReactions.map(r => r.slice(0, 200)),
+      addressed,
+    }),
+    signal: AbortSignal.timeout(10_000),
+  })
+
+  if (!resp.ok) return null
+
+  const data = (await resp.json()) as { reaction?: string }
+  return data.reaction?.trim() || null
+}