feat: 服务管理支持 HTTP/HTTPS 协议选择

- Service 增加 scheme 字段，build_url 按协议拼接地址
- 表单新增协议下拉；启动时自动迁移已有 SQLite 库
- 更新部署说明中的 HTTPS 服务添加示例

Co-authored-by: Cursor <cursoragent@cursor.com>

models.py

@@ -39,6 +39,7 @@ class Service(db.Model):
 
     id = db.Column(db.Integer, primary_key=True)
     name = db.Column(db.String(120), nullable=False)
+    scheme = db.Column(db.String(8), nullable=False, default="http")
     host = db.Column(db.String(255), nullable=False)
     port = db.Column(db.Integer, nullable=False)
     path = db.Column(db.String(512), nullable=False, default="/")
@@ -51,4 +52,7 @@ class Service(db.Model):
         p = (self.path or "/").strip()
         if not p.startswith("/"):
             p = "/" + p
-        return f"http://{self.host}:{self.port}{p}"
+        proto = (self.scheme or "http").strip().lower()
+        if proto not in ("http", "https"):
+            proto = "http"
+        return f"{proto}://{self.host}:{self.port}{p}"