Top-up gasTankAddress() per chain and monitor balances

[buberdds]

After the latest testnet deployment, deposits stopped working: accounting contract's gas tank had a 0 balance, so deposit addresses couldn't be funded with sweep gas.

Checking the tank:

tank addr from a deployed contract:

  cast call 0x910CFfe4e8B27bc367F6E34D6D8e3C31DED68B6f "gasTankAddress()(address)" --rpc-url https://testnet.sapphire.oasis.io

balance on each supported source chain:

cast balance 0x106F3d137Ad5A5992b5702A0772E942669f31ef1 --ether --rpc-url https://sepolia.base.org

Action items:

• Make gas tank top-up a required step in the deployment checklist - both for new contract deployments (new tank address every time) and when adding support for a new chain (same address, new chain, 0 balance)
• Monitor gas tank balances per chain so Privana and dependent apps stay fully functional instead of failing on the first unfundable sweep