[0.x] Add timeout parameter to Agent contract

[Tiagospem]

Add timeout parameter to Agent contract

The Promptable trait already accepts an optional ?int $timeout parameter on prompt() and stream(), but the Agent contract does not declare it. This causes IDE and static analysis warnings (e.g. PHPStan argument.named) when calling ->prompt(..., timeout: 120) on an Agent-typed variable, since the contract signature doesn't include the parameter.

Changes

• Added ?int $timeout = null to Agent::prompt() and Agent::stream() in src/Contracts/Agent.php.

Why

The Promptable trait (used by all concrete agents) already supports timeout on both methods and passes it through to AgentPrompt. The contract simply didn't reflect this, creating a mismatch between the interface and its implementation.

Impact

• Non-breaking: the parameter is optional with a null default.
• Existing tests pass: the 4 timeout-related tests in AgentFakeTest already exercise timeout: as a named argument on both prompt() and stream().