fix: 对话历史上限增至100条 + filterActions 兼容 <app> 动作标签

- 会话历史存储上限从 50 条增至 100 条
- filterActions 同时处理 <action> 和 <app> 标签（DeepSeek 偶用 <app> 替代 <action>）

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/ai-core/cmd/main.go

@@ -133,7 +133,7 @@ func main() {
 	}
 
 	// 初始化会话历史存储
-	convStore := ctxbuild.NewConversationStore(50)
+	convStore := ctxbuild.NewConversationStore(100)
 
 	// 从数据库恢复主会话历史（避免重启丢失上下文）
 	adminUserID := "admin"

backend/platform-bridge/cmd/main.go

@@ -828,36 +828,29 @@ func splitContent(text string) []bridge.ResponseMessage {
 	return msgs
 }
 
-// filterActions removes <action>...</action> tags and their content from text.
-// Also handles unescaped <action> tags from SSE (e.g. <action>).
+// filterActions removes action/emote tags and their content from text.
+// Handles both <action> and <app> tag variants that DeepSeek may produce.
 func filterActions(text string) string {
-	// Remove standard <action>...</action> tags.
-	for {
-		start := strings.Index(text, "<action>")
-		if start == -1 {
-			break
-		}
-		end := strings.Index(text[start:], "</action>")
-		if end == -1 {
-			// Unclosed action tag — just remove the opening tag.
-			text = text[:start] + text[start+len("<action>"):]
-			continue
-		}
-		text = text[:start] + text[start+end+len("</action>"):]
+	// Tags to filter (paired: open → close).
+	actionTags := [][2]string{
+		{"<action>", "</action>"},
+		{"<app>", "</app>"},
 	}
 
-	// Remove SSE-escaped action tags (<action>...</action>).
-	for {
-		start := strings.Index(text, `<action>`)
-		if start == -1 {
-			break
+	for _, tags := range actionTags {
+		openTag, closeTag := tags[0], tags[1]
+		for {
+			start := strings.Index(text, openTag)
+			if start == -1 {
+				break
+			}
+			end := strings.Index(text[start:], closeTag)
+			if end == -1 {
+				text = text[:start] + text[start+len(openTag):]
+				continue
+			}
+			text = text[:start] + text[start+end+len(closeTag):]
 		}
-		end := strings.Index(text[start:], `</action>`)
-		if end == -1 {
-			text = text[:start] + text[start+len(`<action>`):]
-			continue
-		}
-		text = text[:start] + text[start+end+len(`</action>`):]
 	}
 
 	return strings.TrimSpace(text)