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# Deposit Flow

## Deposit

1. User approves the stablecoin (USDC / USDG) to the vault contract.
2. User calls `deposit(amount)`.
3. The contract calls `_accrue()` first — interest is computed deterministically from `block.timestamp`, so there is no discrete rate jump to front-run.
4. Stablecoin is transferred in; receipt shares are minted (round-down, no dilution of earlier holders).
5. A **FIFO lot** is recorded for the deposit, with `maturity = timestamp + 90 days`.

## Interest

* Simple (non-compounding) interest: `interest = totalAssets × apyBps × elapsed / (10000 × 365 days)`.
* Accrues continuously and settles on-chain at the next deposit/redeem.

## Redeem

1. User calls `redeem(shares)`.
2. Requires the deposit's 90-day lot to be mature **and** `withdrawalsOpen == true` (admin-controlled).
3. Receipt shares are burned; the user receives pro-rata principal + accrued yield in the deposit asset.

## Custody / withdrawals

* Only `treasury` can call `withdraw` or `emergencyWithdrawAll`. The `admin` key can configure the cap and open/close deposits & withdrawals but **cannot** move funds.

## Receipt token

Receipt tokens (`ch1USDC`, `chGIWA`) are **soulbound** — non-transferable by design. They represent the user's claim, not a tradeable position.


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