feat: deliverables 3-6 — cold start, simple mode UI, bridge tests, docs

Deliverable 3 — Cold Start Flow:
- New: use-cold-start.ts — cold start detection + greeting management
- Default Chinese greeting for hospital admin users
- Phase tracking: idle → greeting_sent → waiting_response → completed

Deliverable 4 — Simple Mode UI:
- New: uiModeStore.ts — 'simple'|'professional' mode with localStorage
- New: SimpleTopBar.tsx — minimal top bar with mode toggle
- Modified: App.tsx — dual layout rendering based on UI mode
- Modified: ChatArea.tsx — compact prop hides advanced controls
- Default: 'simple' mode for zero-barrier first experience

Deliverable 5 — Tauri Bridge Integration Tests:
- New: tauri-bridge.integration.test.ts — 14 test cases
- Covers: cold start, chat flow, persistence, memory, butler, UI mode, e2e
- 14/14 passing

Deliverable 6 — Release Documentation:
- New: installation-guide.md — user-facing install guide (Chinese, no jargon)
- New: hospital-deployment.md — IT admin deployment guide (Docker, GPO, SCCM)

desktop/src/lib/use-cold-start.ts

@@ -0,0 +1,206 @@
+/**
+ * useColdStart - Cold start state management hook
+ *
+ * Detects first-time users and manages the cold start greeting flow.
+ * Reuses the onboarding completion key to determine if user is new.
+ *
+ * Flow: idle -> greeting_sent -> waiting_response -> completed
+ */
+
+import { useState, useEffect, useCallback } from 'react';
+import { createLogger } from './logger';
+
+const log = createLogger('useColdStart');
+
+// Reuse the same key from use-onboarding.ts
+const ONBOARDING_COMPLETED_KEY = 'zclaw-onboarding-completed';
+
+// Cold start state persisted to localStorage
+const COLD_START_STATE_KEY = 'zclaw-cold-start-state';
+
+// Re-export UserProfile for consumers that need it
+export type { UserProfile } from './use-onboarding';
+
+// === Types ===
+
+export type ColdStartPhase = 'idle' | 'greeting_sent' | 'waiting_response' | 'completed';
+
+export interface ColdStartState {
+  isColdStart: boolean;
+  phase: ColdStartPhase;
+  greetingSent: boolean;
+  markGreetingSent: () => void;
+  markWaitingResponse: () => void;
+  markCompleted: () => void;
+  getGreetingMessage: (agentName?: string, agentEmoji?: string) => string;
+}
+
+// === Default Greeting ===
+
+const DEFAULT_GREETING_BODY =
+  '我可以帮您处理数据报告、会议纪要、政策合规检查等日常工作。\n\n请问您是哪个科室的？主要负责哪方面的工作？';
+
+const FALLBACK_GREETING =
+  '您好！我是您的工作助手。我可以帮您处理数据报告、会议纪要、政策合规检查等工作。请问您是哪个科室的？';
+
+// === Persistence Helpers ===
+
+interface PersistedColdStart {
+  phase: ColdStartPhase;
+}
+
+function loadPersistedPhase(): ColdStartPhase {
+  try {
+    const raw = localStorage.getItem(COLD_START_STATE_KEY);
+    if (raw) {
+      const parsed = JSON.parse(raw) as PersistedColdStart;
+      if (parsed && typeof parsed.phase === 'string') {
+        return parsed.phase;
+      }
+    }
+  } catch (err) {
+    log.warn('Failed to read cold start state:', err);
+  }
+  return 'idle';
+}
+
+function persistPhase(phase: ColdStartPhase): void {
+  try {
+    const data: PersistedColdStart = { phase };
+    localStorage.setItem(COLD_START_STATE_KEY, JSON.stringify(data));
+  } catch (err) {
+    log.warn('Failed to persist cold start state:', err);
+  }
+}
+
+// === Greeting Builder ===
+
+function buildGreeting(agentName?: string, agentEmoji?: string): string {
+  if (!agentName) {
+    return FALLBACK_GREETING;
+  }
+
+  const emoji = agentEmoji ? ` ${agentEmoji}` : '';
+  return `您好！我是${agentName}${emoji}\n\n${DEFAULT_GREETING_BODY}`;
+}
+
+// === Hook ===
+
+/**
+ * Hook to manage cold start state for first-time users.
+ *
+ * A user is considered "cold start" when they have not completed onboarding
+ * AND have not yet gone through the greeting flow.
+ *
+ * Usage:
+ * ```tsx
+ * const { isColdStart, phase, markGreetingSent, getGreetingMessage } = useColdStart();
+ *
+ * if (isColdStart && phase === 'idle') {
+ *   const msg = getGreetingMessage(agent.name, agent.emoji);
+ *   sendMessage(msg);
+ *   markGreetingSent();
+ * }
+ * ```
+ */
+export function useColdStart(): ColdStartState {
+  const [phase, setPhase] = useState<ColdStartPhase>(loadPersistedPhase);
+  const [isColdStart, setIsColdStart] = useState(false);
+
+  // Determine cold start status on mount
+  useEffect(() => {
+    try {
+      const onboardingCompleted = localStorage.getItem(ONBOARDING_COMPLETED_KEY);
+      const isNewUser = onboardingCompleted !== 'true';
+
+      if (isNewUser && phase !== 'completed') {
+        setIsColdStart(true);
+      } else {
+        setIsColdStart(false);
+        // If onboarding is completed but phase is not completed,
+        // force phase to completed to avoid stuck states
+        if (phase !== 'completed') {
+          setPhase('completed');
+          persistPhase('completed');
+        }
+      }
+    } catch (err) {
+      log.warn('Failed to check cold start status:', err);
+      setIsColdStart(false);
+    }
+  }, [phase]);
+
+  const markGreetingSent = useCallback(() => {
+    const nextPhase: ColdStartPhase = 'greeting_sent';
+    setPhase(nextPhase);
+    persistPhase(nextPhase);
+    log.debug('Cold start: greeting sent');
+  }, []);
+
+  const markWaitingResponse = useCallback(() => {
+    const nextPhase: ColdStartPhase = 'waiting_response';
+    setPhase(nextPhase);
+    persistPhase(nextPhase);
+    log.debug('Cold start: waiting for user response');
+  }, []);
+
+  const markCompleted = useCallback(() => {
+    const nextPhase: ColdStartPhase = 'completed';
+    setPhase(nextPhase);
+    persistPhase(nextPhase);
+    setIsColdStart(false);
+    log.debug('Cold start: completed');
+  }, []);
+
+  const getGreetingMessage = useCallback(
+    (agentName?: string, agentEmoji?: string): string => {
+      return buildGreeting(agentName, agentEmoji);
+    },
+    [],
+  );
+
+  return {
+    isColdStart,
+    phase,
+    greetingSent: phase === 'greeting_sent' || phase === 'waiting_response' || phase === 'completed',
+    markGreetingSent,
+    markWaitingResponse,
+    markCompleted,
+    getGreetingMessage,
+  };
+}
+
+// === Non-hook Accessor ===
+
+/**
+ * Get cold start state without React hook (for use outside components).
+ */
+export function getColdStartState(): { isColdStart: boolean; phase: ColdStartPhase } {
+  try {
+    const onboardingCompleted = localStorage.getItem(ONBOARDING_COMPLETED_KEY);
+    const isNewUser = onboardingCompleted !== 'true';
+    const phase = loadPersistedPhase();
+
+    return {
+      isColdStart: isNewUser && phase !== 'completed',
+      phase,
+    };
+  } catch (err) {
+    log.warn('Failed to get cold start state:', err);
+    return { isColdStart: false, phase: 'completed' };
+  }
+}
+
+/**
+ * Reset cold start state (for testing or debugging).
+ */
+export function resetColdStartState(): void {
+  try {
+    localStorage.removeItem(COLD_START_STATE_KEY);
+    log.debug('Cold start state reset');
+  } catch (err) {
+    log.warn('Failed to reset cold start state:', err);
+  }
+}
+
+export default useColdStart;