fix: comprehensive bug fixes and UX improvements for z-dev-v2

This commit includes multiple critical fixes and improvements:

**P0 Fixes (Critical):**
- ✅ Fix trader deletion logic order (manager/trader_manager.go, api/server.go)
  - Added RemoveTrader() method to safely remove traders from memory
  - Fixed order: stop & remove from memory → delete from DB
  - Prevents "ghost traders" running without DB records
  - Clears competition cache on deletion

**P1 Fixes (Important):**
- ✅ Fix two-stage private key input validation (web/src/components/TwoStageKeyModal.tsx)
  - Normalize "0x" prefix before length validation
  - Support keys with or without "0x" prefix
- ✅ Fix competition page showing deleted traders
  - RemoveTrader() now clears competition cache
  - Deleted traders no longer appear in rankings

**P2 Improvements (General):**
- ✅ Add duplicate trader name check (api/server.go)
  - Prevents creating traders with identical names
  - Returns clear error message
- ✅ Improve Dashboard empty state messages (web/src/i18n/translations.ts)
  - More welcoming title: "Let's Get Started!" / "開始使用吧！"
  - Specific action guidance: connect exchange, choose AI model
  - Better call-to-action button text
- ✅ Improve login error messages (web/src/i18n/translations.ts)
  - More helpful error hints
  - Clearer guidance for users

**Cherry-picked from upstream:**
- ✅ Initial balance and equity calculation fixes (NoFxAiOS#901, 4 commits)
- ✅ Dynamic minimum position size for small accounts (NoFxAiOS#902, 1 commit)

Related: NoFxAiOS#787, NoFxAiOS#807, NoFxAiOS#790, NoFxAiOS#813, NoFxAiOS#883
Files changed: 4 (backend: 2, frontend: 2)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: the-dev-z

api/server.go

@@ -486,6 +486,19 @@ func (s *Server) handleCreateTrader(c *gin.Context) {
 		}
 	}
 
+	// ✅ 检查交易员名称是否重复
+	existingTraders, err := s.database.GetTraders(userID)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("检查交易员名称失败: %v", err)})
+		return
+	}
+	for _, existing := range existingTraders {
+		if existing.Name == req.Name {
+			c.JSON(http.StatusBadRequest, gin.H{"error": fmt.Sprintf("交易员名称 '%s' 已存在，请使用其他名称", req.Name)})
+			return
+		}
+	}
+
 	// 生成交易员ID
 	traderID := fmt.Sprintf("%s_%s_%d", req.ExchangeID, req.AIModelID, time.Now().Unix())
 
@@ -794,23 +807,20 @@ func (s *Server) handleDeleteTrader(c *gin.Context) {
 	userID := c.GetString("user_id")
 	traderID := c.Param("id")
 
-	// 从数据库删除
+	// ✅ 步骤1：先从内存中停止并移除交易员（RemoveTrader会处理停止逻辑和竞赛缓存清除）
+	if err := s.traderManager.RemoveTrader(traderID); err != nil {
+		// 交易员不在内存中也不是错误，可能已经被移除或从未加载
+		log.Printf("⚠️ 从内存中移除交易员时出现警告: %v", err)
+	}
+
+	// ✅ 步骤2：最后才从数据库删除
 	err := s.database.DeleteTrader(userID, traderID)
 	if err != nil {
 		c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("删除交易员失败: %v", err)})
 		return
 	}
 
-	// 如果交易员正在运行，先停止它
-	if trader, err := s.traderManager.GetTrader(traderID); err == nil {
-		status := trader.GetStatus()
-		if isRunning, ok := status["is_running"].(bool); ok && isRunning {
-			trader.Stop()
-			log.Printf("⏹  已停止运行中的交易员: %s", traderID)
-		}
-	}
-
-	log.Printf("✓ 交易员已删除: %s", traderID)
+	log.Printf("✓ 交易员已完全删除: %s", traderID)
 	c.JSON(http.StatusOK, gin.H{"message": "交易员已删除"})
 }
 

manager/trader_manager.go

@@ -425,6 +425,48 @@ func (tm *TraderManager) GetTraderIDs() []string {
 	return ids
 }
 
+// RemoveTrader 从内存中移除交易员（删除前必须先停止）
+func (tm *TraderManager) RemoveTrader(traderID string) error {
+	tm.mu.Lock()
+	defer tm.mu.Unlock()
+
+	trader, exists := tm.traders[traderID]
+	if !exists {
+		return fmt.Errorf("trader ID '%s' 不存在", traderID)
+	}
+
+	// 确保交易员已停止
+	status := trader.GetStatus()
+	if status != nil {
+		if isRunning, ok := status["is_running"].(bool); ok && isRunning {
+			log.Printf("⚠️ 交易员 %s 仍在运行，正在停止...", traderID)
+			trader.Stop()
+
+			// 等待停止（最多5秒）
+			for i := 0; i < 50; i++ {
+				time.Sleep(100 * time.Millisecond)
+				status := trader.GetStatus()
+				if running, ok := status["is_running"].(bool); !ok || !running {
+					break
+				}
+			}
+		}
+	}
+
+	// 从map中删除
+	delete(tm.traders, traderID)
+	log.Printf("✅ 已从内存中移除交易员: %s", traderID)
+
+	// 清除竞赛缓存，强制下次重新计算
+	tm.competitionCache.mu.Lock()
+	tm.competitionCache.data = nil
+	tm.competitionCache.timestamp = time.Time{}
+	tm.competitionCache.mu.Unlock()
+	log.Printf("🔄 已清除竞赛缓存")
+
+	return nil
+}
+
 // StartAll 启动所有trader
 func (tm *TraderManager) StartAll() {
 	tm.mu.RLock()

web/src/components/TwoStageKeyModal.tsx

@@ -74,7 +74,9 @@ export function TwoStageKeyModal({
   }, [isOpen, stage])
 
   const handleStage1Next = async () => {
-    if (part1.length < expectedPart1Length) {
+    // ✅ 標準化輸入（移除可能的 0x 前綴）再驗證長度
+    const normalized1 = part1.startsWith('0x') ? part1.slice(2) : part1
+    if (normalized1.length < expectedPart1Length) {
       setError(
         t('errors.privatekeyIncomplete', language, {
           expected: expectedPart1Length,
@@ -129,7 +131,9 @@ export function TwoStageKeyModal({
   }
 
   const handleStage2Complete = () => {
-    if (part2.length < expectedPart2Length) {
+    // ✅ 標準化輸入（移除可能的 0x 前綴）再驗證長度
+    const normalized2 = part2.startsWith('0x') ? part2.slice(2) : part2
+    if (normalized2.length < expectedPart2Length) {
       setError(
         t('errors.privatekeyIncomplete', language, {
           expected: expectedPart2Length,
@@ -138,7 +142,9 @@ export function TwoStageKeyModal({
       return
     }
 
-    const fullKey = part1 + part2
+    // ✅ 拼接時移除可能的 0x 前綴
+    const normalized1 = part1.startsWith('0x') ? part1.slice(2) : part1
+    const fullKey = normalized1 + normalized2
     if (!validatePrivateKeyFormat(fullKey, expectedLength)) {
       setError(t('errors.privatekeyInvalidFormat', language))
       return

web/src/i18n/translations.ts

@@ -146,10 +146,10 @@ export const translations = {
     currentTraders: 'Current Traders',
     noTraders: 'No AI Traders',
     createFirstTrader: 'Create your first AI trader to get started',
-    dashboardEmptyTitle: 'No Traders Configured',
+    dashboardEmptyTitle: "Let's Get Started!",
     dashboardEmptyDescription:
-      "You haven't created any AI traders yet. Create your first trader to start automated trading.",
-    goToTradersPage: 'Go to Traders Page',
+      'Create your first AI trader to automate your trading strategy. Connect an exchange, choose an AI model, and start trading in minutes!',
+    goToTradersPage: 'Create Your First Trader',
     configureModelsFirst: 'Please configure AI models first',
     configureExchangesFirst: 'Please configure exchanges first',
     configureModelsAndExchangesFirst:
@@ -458,9 +458,10 @@ export const translations = {
     completeRegistrationSubtitle: 'to complete registration',
     loginSuccess: 'Login successful',
     registrationSuccess: 'Registration successful',
-    loginFailed: 'Login failed',
-    registrationFailed: 'Registration failed',
-    verificationFailed: 'OTP verification failed',
+    loginFailed: 'Login failed. Please check your email and password.',
+    registrationFailed: 'Registration failed. Please try again.',
+    verificationFailed:
+      'OTP verification failed. Please check the code and try again.',
     invalidCredentials: 'Invalid email or password',
     weak: 'Weak',
     medium: 'Medium',
@@ -947,10 +948,10 @@ export const translations = {
     currentTraders: '当前交易员',
     noTraders: '暂无AI交易员',
     createFirstTrader: '创建您的第一个AI交易员开始使用',
-    dashboardEmptyTitle: '暂无交易员',
+    dashboardEmptyTitle: '开始使用吧！',
     dashboardEmptyDescription:
-      '您还未创建任何AI交易员，创建您的第一个交易员以开始自动化交易。',
-    goToTradersPage: '前往交易员页面',
+      '创建您的第一个 AI 交易员，自动化您的交易策略。连接交易所、选择 AI 模型，几分钟内即可开始交易！',
+    goToTradersPage: '创建您的第一个交易员',
     configureModelsFirst: '请先配置AI模型',
     configureExchangesFirst: '请先配置交易所',
     configureModelsAndExchangesFirst: '请先配置AI模型和交易所',
@@ -1223,9 +1224,9 @@ export const translations = {
     completeRegistrationSubtitle: '以完成注册',
     loginSuccess: '登录成功',
     registrationSuccess: '注册成功',
-    loginFailed: '登录失败',
-    registrationFailed: '注册失败',
-    verificationFailed: 'OTP验证失败',
+    loginFailed: '登录失败，请检查您的邮箱和密码。',
+    registrationFailed: '注册失败，请重试。',
+    verificationFailed: 'OTP 验证失败，请检查验证码后重试。',
     invalidCredentials: '邮箱或密码错误',
     weak: '弱',
     medium: '中',