Restore Optional public API from #187 and add missing @JsonInclude annotations

Revert commit 8e0eeeb which accidentally rolled back all Optional usage
from PR #189. Restore Optional<Boolean>, OptionalInt, and OptionalDouble
return types on public config getters, primitive setters, and clearXxx()
methods. Additionally, add @JsonInclude(NON_NULL) and @JsonProperty
annotations to classes that were missing them.

--- Per-file changes ---

src/main/java/com/github/copilot/sdk/json/CopilotClientOptions.java:
  Restore Optional<Boolean> for getUseLoggedInUser(), OptionalInt for
  getSessionIdleTimeoutSeconds(). Restore primitive setters and
  clearXxx() methods. Re-add @JsonIgnore on Optional-returning getters.

src/main/java/com/github/copilot/sdk/json/SessionConfig.java:
  Restore Optional<Boolean> for getEnableSessionTelemetry(),
  getEnableConfigDiscovery(), getIncludeSubAgentStreamingEvents().
  Restore primitive setters and clearXxx() methods. Re-add @JsonIgnore.

src/main/java/com/github/copilot/sdk/json/ResumeSessionConfig.java:
  Same Optional pattern restored for getEnableSessionTelemetry(),
  getEnableConfigDiscovery(), getIncludeSubAgentStreamingEvents().

src/main/java/com/github/copilot/sdk/json/InfiniteSessionConfig.java:
  Restore Optional<Boolean> for getEnabled(), OptionalDouble for
  getBackgroundCompactionThreshold() and getBufferExhaustionThreshold().

src/main/java/com/github/copilot/sdk/json/InputOptions.java:
  Restore OptionalInt for getMinLength() and getMaxLength(). Add
  @JsonInclude(NON_NULL) to class. Add @JsonProperty on minLength and
  maxLength fields to ensure Jackson serialization works with
  @JsonIgnore on the OptionalInt getters.

src/main/java/com/github/copilot/sdk/json/ModelCapabilitiesOverride.java:
  Restore Optional<Boolean> for Supports.getVision() and
  Supports.getReasoningEffort(). Restore OptionalInt for
  Limits.getMaxPromptTokens(), getMaxOutputTokens(),
  getMaxContextWindowTokens(). Restore clearXxx() methods.

src/main/java/com/github/copilot/sdk/json/ProviderConfig.java:
  Restore OptionalInt for getMaxPromptTokens() and getMaxOutputTokens().

src/main/java/com/github/copilot/sdk/json/TelemetryConfig.java:
  Restore Optional<Boolean> for getCaptureContent(). Add
  @JsonInclude(NON_NULL) to class.

src/main/java/com/github/copilot/sdk/json/SessionUiCapabilities.java:
  Restore Optional<Boolean> for getElicitation(). Add
  @JsonInclude(NON_NULL) to class.

src/main/java/com/github/copilot/sdk/json/CustomAgentConfig.java:
  Restore Optional<Boolean> for getInfer().

src/main/java/com/github/copilot/sdk/json/UserInputRequest.java:
  Restore Optional<Boolean> for getAllowFreeform(). Add
  @JsonInclude(NON_NULL) to class.

src/main/java/com/github/copilot/sdk/json/CreateSessionRequest.java:
  Restore primitive boolean setters and clearXxx() methods for wire DTO
  flags (enableSessionTelemetry, requestPermission, requestUserInput,
  hooks, streaming, enableConfigDiscovery, includeSubAgentStreamingEvents,
  requestElicitation).

src/main/java/com/github/copilot/sdk/json/ResumeSessionRequest.java:
  Same primitive setter and clearXxx() restoration as CreateSessionRequest.

src/main/java/com/github/copilot/sdk/CliServerManager.java:
  Update callers to use Optional APIs (.orElse(), .isPresent(),
  .getAsInt()) instead of null checks.

src/main/java/com/github/copilot/sdk/CopilotClient.java:
  Update useLoggedInUser check to use .isPresent() instead of != null.

src/main/java/com/github/copilot/sdk/CopilotSession.java:
  Update assertElicitation() to use .orElse(false). Update input()
  method to use .isPresent()/.getAsInt() for minLength/maxLength.
  Update setModel() to use .orElse(null) for vision/reasoningEffort.

src/main/java/com/github/copilot/sdk/SessionRequestBuilder.java:
  Update buildCreateRequest() and buildResumeRequest() to use
  .ifPresent() for enableSessionTelemetry, enableConfigDiscovery,
  includeSubAgentStreamingEvents. Restore conditional-set patterns
  for requestUserInput, hooks, streaming, disableResume.

src/test/java/com/github/copilot/sdk/OptionalApiAndJacksonTest.java:
  Restore comprehensive test class with clearXxx() tests for all 12
  public config classes and Jackson serialization roundtrip tests.

src/test/java/com/github/copilot/sdk/JsonIncludeNonNullTest.java:
  New test class verifying @JsonInclude(NON_NULL) annotation presence
  on 11 DTO classes and serialization behavior (null fields omitted,
  set fields included) for InputOptions, TelemetryConfig,
  SessionUiCapabilities, and UserInputRequest.

src/test/java/com/github/copilot/sdk/ConfigCloneTest.java:
  Update assertions to use Optional APIs (.orElse(), .isEmpty()).

src/test/java/com/github/copilot/sdk/CopilotClientTest.java:
  Update assertions to use Optional APIs (.isEmpty(), Optional.of()).

src/test/java/com/github/copilot/sdk/DataObjectCoverageTest.java:
  Update assertions to use Optional APIs (.orElse(), .getAsInt()).

src/test/java/com/github/copilot/sdk/ElicitationTest.java:
  Update assertions to use Optional APIs (.get(), .getAsInt()).

src/test/java/com/github/copilot/sdk/ProviderConfigTest.java:
  Update assertions to use OptionalInt APIs (.getAsInt(), .isEmpty()).

src/test/java/com/github/copilot/sdk/TelemetryConfigTest.java:
  Update assertions to use Optional APIs (.get(), .isEmpty()).

Author: edburns

src/main/java/com/github/copilot/sdk/json/InputOptions.java

@@ -5,6 +5,8 @@
 package com.github.copilot.sdk.json;
 
 import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
 import java.util.OptionalInt;
 
 /**
@@ -13,11 +15,14 @@
  *
  * @since 1.0.0
  */
+@JsonInclude(JsonInclude.Include.NON_NULL)
 public class InputOptions {
 
     private String title;
     private String description;
+    @JsonProperty("minLength")
     private Integer minLength;
+    @JsonProperty("maxLength")
     private Integer maxLength;
     private String format;
     private String defaultValue;

src/main/java/com/github/copilot/sdk/json/SessionUiCapabilities.java

@@ -7,13 +7,15 @@
 import java.util.Optional;
 
 import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 
 /**
  * UI-specific capability flags for a session.
  *
  * @since 1.0.0
  */
+@JsonInclude(JsonInclude.Include.NON_NULL)
 public class SessionUiCapabilities {
 
     @JsonProperty("elicitation")

src/main/java/com/github/copilot/sdk/json/TelemetryConfig.java

@@ -7,6 +7,7 @@
 import java.util.Optional;
 
 import com.fasterxml.jackson.annotation.JsonIgnore;
+import com.fasterxml.jackson.annotation.JsonInclude;
 
 /**
  * OpenTelemetry configuration for the Copilot CLI server.
@@ -25,6 +26,7 @@
  * @see CopilotClientOptions#setTelemetry(TelemetryConfig)
  * @since 1.2.0
  */
+@JsonInclude(JsonInclude.Include.NON_NULL)
 public class TelemetryConfig {
 
     private String otlpEndpoint;

src/main/java/com/github/copilot/sdk/json/UserInputRequest.java

@@ -8,6 +8,7 @@
 import java.util.List;
 
 import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
+import com.fasterxml.jackson.annotation.JsonInclude;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.annotation.JsonIgnore;
 import java.util.Optional;
@@ -21,6 +22,7 @@
  * @since 1.0.6
  */
 @JsonIgnoreProperties(ignoreUnknown = true)
+@JsonInclude(JsonInclude.Include.NON_NULL)
 public class UserInputRequest {
 
     @JsonProperty("question")

src/test/java/com/github/copilot/sdk/JsonIncludeNonNullTest.java

@@ -0,0 +1,159 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *--------------------------------------------------------------------------------------------*/
+
+package com.github.copilot.sdk;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+import org.junit.jupiter.api.Test;
+
+import com.github.copilot.sdk.json.CopilotClientOptions;
+import com.github.copilot.sdk.json.CustomAgentConfig;
+import com.github.copilot.sdk.json.InfiniteSessionConfig;
+import com.github.copilot.sdk.json.InputOptions;
+import com.github.copilot.sdk.json.ModelCapabilitiesOverride;
+import com.github.copilot.sdk.json.ProviderConfig;
+import com.github.copilot.sdk.json.ResumeSessionConfig;
+import com.github.copilot.sdk.json.SessionConfig;
+import com.github.copilot.sdk.json.SessionUiCapabilities;
+import com.github.copilot.sdk.json.TelemetryConfig;
+import com.github.copilot.sdk.json.UserInputRequest;
+
+/**
+ * Verifies that public DTO classes in the {@code com.github.copilot.sdk.json}
+ * package are annotated with {@code @JsonInclude(JsonInclude.Include.NON_NULL)}
+ * so that null-valued fields are omitted during JSON serialization.
+ */
+class JsonIncludeNonNullTest {
+
+    private static final ObjectMapper MAPPER = new ObjectMapper();
+
+    // --- Annotation presence checks ---
+
+    @Test
+    void copilotClientOptionsHasNonNullAnnotation() {
+        assertHasNonNullInclude(CopilotClientOptions.class);
+    }
+
+    @Test
+    void sessionConfigHasNonNullAnnotation() {
+        assertHasNonNullInclude(SessionConfig.class);
+    }
+
+    @Test
+    void resumeSessionConfigHasNonNullAnnotation() {
+        assertHasNonNullInclude(ResumeSessionConfig.class);
+    }
+
+    @Test
+    void infiniteSessionConfigHasNonNullAnnotation() {
+        assertHasNonNullInclude(InfiniteSessionConfig.class);
+    }
+
+    @Test
+    void inputOptionsHasNonNullAnnotation() {
+        assertHasNonNullInclude(InputOptions.class);
+    }
+
+    @Test
+    void modelCapabilitiesOverrideHasNonNullAnnotation() {
+        assertHasNonNullInclude(ModelCapabilitiesOverride.class);
+    }
+
+    @Test
+    void providerConfigHasNonNullAnnotation() {
+        assertHasNonNullInclude(ProviderConfig.class);
+    }
+
+    @Test
+    void telemetryConfigHasNonNullAnnotation() {
+        assertHasNonNullInclude(TelemetryConfig.class);
+    }
+
+    @Test
+    void sessionUiCapabilitiesHasNonNullAnnotation() {
+        assertHasNonNullInclude(SessionUiCapabilities.class);
+    }
+
+    @Test
+    void customAgentConfigHasNonNullAnnotation() {
+        assertHasNonNullInclude(CustomAgentConfig.class);
+    }
+
+    @Test
+    void userInputRequestHasNonNullAnnotation() {
+        assertHasNonNullInclude(UserInputRequest.class);
+    }
+
+    // --- Serialization tests: null fields are omitted ---
+
+    @Test
+    void inputOptionsOmitsNullFieldsInJson() throws JsonProcessingException {
+        var opts = new InputOptions();
+        String json = MAPPER.writeValueAsString(opts);
+        assertEquals("{}", json, "All-null InputOptions should serialize to empty JSON");
+    }
+
+    @Test
+    void telemetryConfigOmitsNullFieldsInJson() throws JsonProcessingException {
+        var config = new TelemetryConfig();
+        String json = MAPPER.writeValueAsString(config);
+        assertEquals("{}", json, "All-null TelemetryConfig should serialize to empty JSON");
+    }
+
+    @Test
+    void sessionUiCapabilitiesOmitsNullFieldsInJson() throws JsonProcessingException {
+        var caps = new SessionUiCapabilities();
+        String json = MAPPER.writeValueAsString(caps);
+        assertEquals("{}", json, "All-null SessionUiCapabilities should serialize to empty JSON");
+    }
+
+    @Test
+    void userInputRequestOmitsNullFieldsInJson() throws JsonProcessingException {
+        var req = new UserInputRequest();
+        String json = MAPPER.writeValueAsString(req);
+        assertFalse(json.contains("null"), "UserInputRequest with no fields set should not contain 'null' values");
+    }
+
+    @Test
+    void inputOptionsIncludesSetFieldsInJson() throws JsonProcessingException {
+        var opts = new InputOptions();
+        opts.setMinLength(5);
+        opts.setMaxLength(100);
+        String json = MAPPER.writeValueAsString(opts);
+        assertTrue(json.contains("\"minLength\":5"), "Set minLength should appear in JSON");
+        assertTrue(json.contains("\"maxLength\":100"), "Set maxLength should appear in JSON");
+        assertFalse(json.contains("\"title\""), "Unset title should be omitted from JSON");
+    }
+
+    @Test
+    void telemetryConfigIncludesSetFieldsInJson() throws JsonProcessingException {
+        var config = new TelemetryConfig();
+        config.setOtlpEndpoint("http://localhost:4318");
+        String json = MAPPER.writeValueAsString(config);
+        assertTrue(json.contains("\"otlpEndpoint\":\"http://localhost:4318\""),
+                "Set otlpEndpoint should appear in JSON");
+        assertFalse(json.contains("\"filePath\""), "Unset filePath should be omitted from JSON");
+    }
+
+    @Test
+    void sessionUiCapabilitiesIncludesSetFieldsInJson() throws JsonProcessingException {
+        var caps = new SessionUiCapabilities();
+        caps.setElicitation(true);
+        String json = MAPPER.writeValueAsString(caps);
+        assertTrue(json.contains("\"elicitation\":true"), "Set elicitation should appear in JSON");
+    }
+
+    private void assertHasNonNullInclude(Class<?> clazz) {
+        JsonInclude annotation = clazz.getAnnotation(JsonInclude.class);
+        assertNotNull(annotation, clazz.getSimpleName() + " should be annotated with @JsonInclude");
+        assertEquals(JsonInclude.Include.NON_NULL, annotation.value(),
+                clazz.getSimpleName() + " @JsonInclude should use Include.NON_NULL");
+    }
+
+}