When are the energy and power pool cleanup? Like, can I tap a seal at the beginning of a turn before it readies to have it 2 times?

Your Rune Pool empties at exactly two times: after the Draw Phase (Rule 166, 315.4.d) and at the end of each turn (Expiration Step, Rule 317.2.d). Any unspent Energy or Power is lost at both points.

No, you cannot double-tap a Seal this way.

Here's the turn sequence that blocks it:

1. End of previous turn — your Rune Pool empties. Any power left over from last turn is already gone.
2. Awaken Phase (Rule 315.1) — the very first thing at the start of your turn: you Ready all game objects you control. So a Seal that was tapped last turn becomes ready immediately.
3. Draw Phase (Rule 315.4) — after you draw, your Rune Pool empties again.
4. Main Phase — this is when you can finally activate Gear abilities (they require Main Phase + Open State unless they have Reaction, Rule 150.2).

So at no point can you tap a Seal "before it readies." The Awaken Phase readies it first, and any past-turn power was wiped during the end-of-turn cleanup. You get one tap per turn from the Seal during your Main Phase, which is all it's intended to provide.