[ai] Add WithCallOptions functional option (#518)

## Summary
Add a new functional option to pass an entire options struct.

## How was it tested?
Added unit tests.

## Community Contribution License

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project maintainers under the terms of the [Apache 2
License](https://www.apache.org/licenses/LICENSE-2.0).

By creating this pull request I represent that I have the right to
license the contributions to the project maintainers under the Apache 2
License as stated in the [Community Contribution
License](https://github.com/jetify-com/opensource/blob/main/CONTRIBUTING.md#community-contribution-license).

Author: loreto

aisdk/ai/options.go

@@ -127,6 +127,14 @@ func WithProviderMetadata(providerName string, metadata any) GenerateOption {
 	}
 }
 
+// WithCallOptions sets the entire CallOptions struct.
+// This allows passing a pre-configured CallOptions instance.
+func WithCallOptions(callOptions api.CallOptions) GenerateOption {
+	return func(o *GenerateOptions) {
+		o.CallOptions = callOptions
+	}
+}
+
 // buildGenerateConfig combines multiple generate options into a single GenerateConfig struct.
 func buildGenerateConfig(opts []GenerateOption) GenerateOptions {
 	config := GenerateOptions{

aisdk/ai/options_test.go

@@ -154,6 +154,29 @@ func TestCallOptionBuilders(t *testing.T) {
 				Model: &mockLanguageModel{name: "test-model"},
 			},
 		},
+		{
+			name: "WithCallOptions",
+			option: WithCallOptions(api.CallOptions{
+				MaxOutputTokens:  500,
+				Temperature:      pointer.Float64(0.5),
+				TopP:             0.8,
+				StopSequences:    []string{"END"},
+				Seed:             123,
+				PresencePenalty:  0.1,
+				FrequencyPenalty: 0.2,
+			}),
+			expected: GenerateOptions{
+				CallOptions: api.CallOptions{
+					MaxOutputTokens:  500,
+					Temperature:      pointer.Float64(0.5),
+					TopP:             0.8,
+					StopSequences:    []string{"END"},
+					Seed:             123,
+					PresencePenalty:  0.1,
+					FrequencyPenalty: 0.2,
+				},
+			},
+		},
 	}
 
 	for _, tt := range tests {