The Portal is the entry point of the Flap bonding curve protocol. It launches standard tokens and tax tokens and wires them to the bonding curve lifecycle. For each tax token launched, if the "funds recipient wallet" percentage is set to non-zero, a portion or all tax revenue is sent to that wallet. And when that wallet is a smart contract and implements Vault interface, it is called a Vault.
The VaultPortal builds on top of the Portal to add Vault functionality for tax tokens. It launches a tax token and sets up a Vault in one flow.