Support multiple concurrent sessions (multi-account / team use case)

[Cheelax]

Use Case
We're building an agent that plays on behalf of a team of players. Each player has their own Cartridge Controller wallet. The agent runs on a single VPS and needs to execute transactions for multiple accounts.

Currently, the CLI stores one active session in ~/.config/controller-cli/ with a single @cartridge/active pointer. Running session auth for a second account overwrites the first session.

What we'd like
The ability to store and use multiple sessions simultaneously on the same machine. For example:

# Auth multiple accounts
controller session auth --file policy.json --chain-id SN_MAIN --account player1
controller session auth --file policy.json --chain-id SN_MAIN --account player2

# Execute with a specific account
controller execute <contract> <entrypoint> [...calldata] --account player1 --chain-id SN_MAIN
controller execute <contract> <entrypoint> [...calldata] --account player2 --chain-id SN_MAIN

# Check status per account
controller session status --account player1 --json
# Auth multiple accounts
controller session auth --file policy.json --chain-id SN_MAIN --account player1
controller session auth --file policy.json --chain-id SN_MAIN --account player2

# Execute with a specific account
controller execute <contract> <entrypoint> [...calldata] --account player1 --chain-id SN_MAIN
controller execute <contract> <entrypoint> [...calldata] --account player2 --chain-id SN_MAIN

# Check status per account
controller session status --account player1 --json
Current workaround