Vedas are endless divine sounds.
Vyasa divided them into 4 - Rig, Yajur, Sama, Atharva
Veda Angas (parts) are a requirement to understand the sounds of Vedas.
There are 6 Veda Angas - shiksha, chandas, vyakaraṇa, nirukta, kalpa, jyotiṣha
'Shasanaat (or Shaasthi) iti Shastra' - that which orders is called shastra.
'Shastrayonitvat' - Brahma Sutra 1.1.2
Bhagavan can be understood only through Shastras
Commentary - "He who is ignorant of Srutis can not know that Supreme Being"
shastras = sruti = revelation = vedas
From this one might conclude that Shastras means Vedas (ONLY).
They would not be wrong.
But they would not be right, either.
Because the very immediate next question would be - 'great, now how do I learn and abide by Vedas?'
And that's where they get you. We are not a rishi yet to directly hear vedas through tapas/meditation. Translation of Vedic sounds into local languages does constitute 'revelation'. So we have to rely on the 6 Veda Angas to understand them.
And the very next question would be 'ok, how do I learn veda angas?'
Well, we are not sanskrit scholar yet to directly understand veda angas through study. So we have to rely on the 4 Upa-Angas: purana, nyaya, mimamsa, dharmashastra
dharma shastra = bhashya(explanation/commentary) of dharma sutra = bhashya of part of kalpa.
And the very next question would be 'ok, how do I learn dharma shastra?'
Well, we don't have the time, energy or inclination to understand these either yet. So we have to rely on our elders and acharyas.
So, the answer to your question - "is it Sruti OR Smriti?"
"if You = Rishi then Sruti else Smriti"