  Simulations of the $\Lambda$-hyperon and light-hypernuclei production in
Au+Au collisions at $\sqrt{s_{NN}}=$ 3 GeV were performed within updated
Three-fluid Hydrodynamics-based Event Simulator Extended by UrQMD
(Ultra-relativistic Quantum Molecular Dynamics) final State interactions
(THESEUS). The light (hyper)nuclei are treated thermodynamically, i.e. they are
considered on the equal basis with hadrons. The only additional parameter is
related to the late freeze-out that imitates the afterburner stage for the
light (hyper)nuclei because the UrQMD is not able to dynamically treat them.
The calculation of hypernuclei production is completely similar to that of
light nuclei. The hypernuclei results are compared with recent STAR data. It is
found that the calculated midrapidity $_\Lambda^3$H/$\Lambda$ ratio falls
within the error bars of the experimental point. It is remarkable that large
difference between the $t/p$ and $_\Lambda^3$H/$\Lambda$ ratios is reproduced
without any additional parameters. Rapidity distributions of
$_\Lambda^3$H/$\Lambda$ and $_\Lambda^4$He/$\Lambda$ ratios are predicted.
Midrapidity mean transverse momenta of protons, $\Lambda$s and light
(hyper)nuclei in central collisions well agree with the data. The calculated
directed flow also reasonably well reproduces of the data.
