[0.x] Add tool call assertions for agent responses

[yousefkadah]

Summary

Adds three assertions for verifying which tools an agent invoked while producing a TextResponse, plus matching static helpers on the Promptable trait so they can be called from any agent class.

$response = (new SalesCoach)->prompt('Find me wines from Napa Valley');

Ai::assertAgentCalledTool($response, 'search_wines');
Ai::assertAgentCalledTool($response, 'search_wines', ['region' => 'napa']);
Ai::assertAgentCalledTool($response, 'search_wines', fn (array $args) => str_contains($args['query'], 'napa'));
Ai::assertAgentDidNotCallTool($response, 'delete_database');
Ai::assertAgentCalledNoTools($greetingResponse);

// Or via the static helpers on the agent class
SalesCoach::assertCalledTool($response, 'search_wines');
SalesCoach::assertDidNotCallTool($response, 'delete_database');
SalesCoach::assertCalledNoTools($greetingResponse);

Methods added

On Concerns\InteractsWithFakeAgents (auto-exposed via the Ai facade since AiManager uses the trait):

• assertAgentCalledTool(TextResponse $response, string $tool, Closure|array|null $arguments = null)
• assertAgentDidNotCallTool(TextResponse $response, string $tool)
• assertAgentCalledNoTools(TextResponse $response)

The third argument of assertAgentCalledTool may be:

• null to match any invocation of the tool
• an array of arguments that must be a subset of the recorded call's arguments (recursively for nested arrays — useful when the model adds optional fields you don't want to assert on)
• a Closure that receives the recorded arguments and returns a bool (with the full ToolCall instance as a second argument for advanced inspection)

This mirrors the existing assertAgentWasPrompted API which already accepts both string and Closure callbacks.

Matching static helpers were added to the Promptable trait:

• Promptable::assertCalledTool(...)
• Promptable::assertDidNotCallTool(...)
• Promptable::assertCalledNoTools(...)

Why no gateway / response changes

All assertion data already lives on TextResponse->toolCalls (a Collection<ToolCall>). The new methods are pure consumers of that data, so this PR touches zero gateway, provider, or response classes.

Tests

A new file tests/Feature/AgentToolAssertionsTest.php adds 17 Pest tests / 37 assertions covering:

• Single and multi-tool responses
• Failure messages for the named tool not being called
• Exact-match argument subsets, nested argument subsets, and missing arguments
• Closure-based argument matching (pass and fail)
• The static Promptable helpers
• Empty-response and multi-call cases for assertAgentCalledNoTools

Tests:    17 passed (37 assertions)
Duration: 0.25s

tests/Feature/AgentFakeTest.php (the existing related test file) still passes alongside the new file:

Tests:    37 passed (76 assertions)

Pint is clean on every changed file.

Why this is useful

Agent evaluation is a core pillar of LLM testing (DeepEval, RAGAS both ship tool-call assertions). The Laravel AI SDK already has rich primitives for asserting that an agent was prompted, but no first-class way to assert which tools the agent called or with what arguments — currently you'd have to reach into $response->toolCalls and write the loop yourself in every test.