feat: 接通 Database 凭据准备闭环

internal/database/application/application_credential.go

@@ -88,6 +88,13 @@ func (c ApplicationCredential) Validate() error {
 	return err
 }
 
+// MatchesTarget 只比较连接目标，不向用例暴露密码；管理库名不是应用连接目标的一部分。
+func (c ApplicationCredential) MatchesTarget(username, database string, endpoint instance.Endpoint) bool {
+	actual, wanted := c.endpoint.Values(), endpoint.Values()
+	return c.username == username && c.database == database && actual.Host == wanted.Host &&
+		actual.HostAddr == wanted.HostAddr && actual.Port == wanted.Port && actual.TLSMode == wanted.TLSMode
+}
+
 // ParseApplicationCredential 拒绝缺键、非字符串或非法连接参数，不回显后端内容。
 func ParseApplicationCredential(data map[string]any) (ApplicationCredential, error) {
 	values := make(map[string]string, 7)