fix: 修正 OpenAI/Anthropic Provider 初始化参数顺序

修复 manager.go 中两处调用 NewOpenAIProvider 和 NewAnthropicProvider
时参数顺序错误的问题。原代码将 baseURL 和 apiKey 参数传反，导致
API key 被当作 URL 使用，引发 "unsupported protocol scheme" 错误。

Changed:
- LoadProvidersFromDB: 调整参数顺序为 (apiKey, baseURL, "")
- GetActiveProvider: 调整参数顺序为 (apiKey, baseURL, "")

server/cmd/seed-providers/main.go

@@ -0,0 +1,66 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"os"
+
+	"github.com/jackc/pgx/v5/pgxpool"
+	"github.com/joho/godotenv"
+)
+
+func main() {
+	_ = godotenv.Load("../../.env")
+
+	databaseURL := os.Getenv("DATABASE_URL")
+	if databaseURL == "" {
+		log.Fatal("DATABASE_URL 环境变量未设置")
+	}
+
+	ctx := context.Background()
+	pool, err := pgxpool.New(ctx, databaseURL)
+	if err != nil {
+		log.Fatalf("连接数据库失败: %v", err)
+	}
+	defer pool.Close()
+
+	// 插入阿里云百炼（通义千问）配置
+	sql := `
+		INSERT INTO model_providers (
+			name,
+			base_url,
+			api_key_encrypted,
+			models,
+			is_active,
+			priority,
+			config
+		) VALUES (
+			'阿里云百炼 (通义千问)',
+			'https://dashscope.aliyuncs.com/compatible-mode/v1',
+			'sk-c0c5174892c44ff48d587cd040fbdd40',
+			'[
+				{"id": "qwen-plus", "name": "通义千问-Plus", "type": "chat"},
+				{"id": "qwen-turbo", "name": "通义千问-Turbo", "type": "chat"},
+				{"id": "qwen-max", "name": "通义千问-Max", "type": "chat"},
+				{"id": "qwen-long", "name": "通义千问-Long", "type": "chat"}
+			]'::jsonb,
+			true,
+			100,
+			'{
+				"provider": "openai",
+				"default_model": "qwen-plus",
+				"supports_function_calling": true,
+				"supports_streaming": true
+			}'::jsonb
+		)
+		ON CONFLICT DO NOTHING
+	`
+
+	_, err = pool.Exec(ctx, sql)
+	if err != nil {
+		log.Fatalf("插入数据失败: %v", err)
+	}
+
+	fmt.Println("✅ 成功初始化模型提供商数据：阿里云百炼 (通义千问)")
+}