feat(wcp): execution boundary semantics + checkpoint methods (v5.4.0)

* feat(wcp): add retryPolicy to StepGateRequest + cached/decisionSource to StepGateResponse

Support execution boundary semantics (#1414): retryPolicy field with
builder method on StepGateRequest, cached (boolean) and decisionSource
fields on StepGateResponse. Backward-compatible constructors preserved.

* feat(wcp): add Checkpoint, CheckpointListResponse, ResumeFromCheckpointResponse types

New types for checkpoint operations. Jackson-annotated with @JsonCreator
for deserialization.

* feat(wcp): add checkpoint client methods + version 5.4.0 + changelog

Author: saurabhjain1592

CHANGELOG.md

@@ -5,6 +5,23 @@ All notable changes to the AxonFlow Java SDK will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [5.4.0] - 2026-04-18
+
+### Added
+
+- **Execution boundary semantics** — `retryPolicy` field on `StepGateRequest`
+  (via builder: `.retryPolicy("reevaluate")`). Controls cached vs fresh
+  evaluation for the same step boundary.
+- **Step gate response metadata** — `cached` (boolean) and `decisionSource`
+  (String) fields on `StepGateResponse` via `isCached()` and
+  `getDecisionSource()`.
+- **Workflow checkpoints** — `getCheckpoints(workflowId)` lists step-gate
+  checkpoints. `resumeFromLastCheckpoint(workflowId)` resumes from last
+  checkpoint (Evaluation+). `resumeFromCheckpoint(workflowId, checkpointId)`
+  resumes from a specific checkpoint (Enterprise).
+- **Checkpoint types** — `Checkpoint`, `CheckpointListResponse`, and
+  `ResumeFromCheckpointResponse` with Jackson deserialization.
+
 ## [5.3.0] - 2026-04-09
 
 ### Added

pom.xml

@@ -6,7 +6,7 @@
 
     <groupId>com.getaxonflow</groupId>
     <artifactId>axonflow-sdk</artifactId>
-    <version>5.3.0</version>
+    <version>5.4.0</version>
     <packaging>jar</packaging>
 
     <name>AxonFlow Java SDK</name>

src/main/java/com/getaxonflow/sdk/AxonFlow.java

@@ -5135,6 +5135,79 @@ public void resumeWorkflow(String workflowId) {
         "resumeWorkflow");
   }
 
+  /**
+   * Lists step-gate checkpoints for a workflow. Available in all tiers.
+   *
+   * @param workflowId workflow ID
+   * @return checkpoint list
+   */
+  public com.getaxonflow.sdk.types.workflow.WorkflowTypes.CheckpointListResponse getCheckpoints(
+      String workflowId) {
+    Objects.requireNonNull(workflowId, "workflowId cannot be null");
+    return retryExecutor.execute(
+        () -> {
+          Request httpRequest =
+              buildOrchestratorRequest("GET", "/api/v1/workflows/" + workflowId + "/checkpoints", null);
+          try (Response response = httpClient.newCall(httpRequest).execute()) {
+            return parseResponse(
+                response,
+                new TypeReference<
+                    com.getaxonflow.sdk.types.workflow.WorkflowTypes.CheckpointListResponse>() {});
+          }
+        },
+        "getCheckpoints");
+  }
+
+  /**
+   * Resumes a workflow from its last resumable checkpoint. Evaluation+ tier.
+   *
+   * @param workflowId workflow ID
+   * @return resume result with fresh decision
+   */
+  public com.getaxonflow.sdk.types.workflow.WorkflowTypes.ResumeFromCheckpointResponse resumeFromLastCheckpoint(
+      String workflowId) {
+    Objects.requireNonNull(workflowId, "workflowId cannot be null");
+    return retryExecutor.execute(
+        () -> {
+          Request httpRequest =
+              buildOrchestratorRequest("POST", "/api/v1/workflows/" + workflowId + "/checkpoints/resume", "{}");
+          try (Response response = httpClient.newCall(httpRequest).execute()) {
+            return parseResponse(
+                response,
+                new TypeReference<
+                    com.getaxonflow.sdk.types.workflow.WorkflowTypes.ResumeFromCheckpointResponse>() {});
+          }
+        },
+        "resumeFromLastCheckpoint");
+  }
+
+  /**
+   * Resumes a workflow from a specific checkpoint. Enterprise only.
+   *
+   * @param workflowId workflow ID
+   * @param checkpointId checkpoint database ID
+   * @return resume result with fresh decision
+   */
+  public com.getaxonflow.sdk.types.workflow.WorkflowTypes.ResumeFromCheckpointResponse resumeFromCheckpoint(
+      String workflowId, long checkpointId) {
+    Objects.requireNonNull(workflowId, "workflowId cannot be null");
+    return retryExecutor.execute(
+        () -> {
+          Request httpRequest =
+              buildOrchestratorRequest(
+                  "POST",
+                  "/api/v1/workflows/" + workflowId + "/checkpoints/" + checkpointId + "/resume",
+                  "{}");
+          try (Response response = httpClient.newCall(httpRequest).execute()) {
+            return parseResponse(
+                response,
+                new TypeReference<
+                    com.getaxonflow.sdk.types.workflow.WorkflowTypes.ResumeFromCheckpointResponse>() {});
+          }
+        },
+        "resumeFromCheckpoint");
+  }
+
   /**
    * Lists workflows with optional filters.
    *