feat(api): support quarantined inbound message processing

Author: bjarn

src/main/java/co/lettermint/api/ApiClient.java

@@ -145,6 +145,10 @@ public RescheduleMessageResponse cancel(String messageId) {
             return client.post("/messages/" + segment(messageId) + "/cancel", null, RescheduleMessageResponse.class);
         }
 
+        public ProcessInboundMessageResponse process(String messageId) {
+            return client.post("/messages/" + segment(messageId) + "/process", null, ProcessInboundMessageResponse.class);
+        }
+
         public MessageEventsResponse events(String messageId) {
             return events(messageId, null);
         }

src/main/java/co/lettermint/models/api/MessageEventType.java

@@ -22,6 +22,7 @@ public final class MessageEventType {
     public static final String INBOUNDRECEIVED = "inbound_received";
     public static final String INBOUNDQUEUED = "inbound_queued";
     public static final String INBOUNDSPAMBLOCKED = "inbound_spam_blocked";
+    public static final String INBOUNDRELEASED = "inbound_released";
     public static final String INBOUNDPROCESSED = "inbound_processed";
     public static final String INBOUNDRETRY = "inbound_retry";
 

src/main/java/co/lettermint/models/api/MessageStatus.java

@@ -4,6 +4,7 @@ public final class MessageStatus {
     public static final String SCHEDULED = "scheduled";
     public static final String PENDING = "pending";
     public static final String QUEUED = "queued";
+    public static final String QUARANTINED = "quarantined";
     public static final String SUPPRESSED = "suppressed";
     public static final String PROCESSED = "processed";
     public static final String DELIVERED = "delivered";

src/main/java/co/lettermint/models/api/ProcessInboundMessageResponse.java

@@ -0,0 +1,11 @@
+package co.lettermint.models.api;
+
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import java.util.Map;
+
+@JsonIgnoreProperties(ignoreUnknown = true)
+public class ProcessInboundMessageResponse {
+    @JsonProperty("data")
+    public Map<String, Object> data;
+}

src/test/java/co/lettermint/ApiClientTest.java

@@ -150,13 +150,15 @@ void schedulesMessageChangesWithTypedResponses() throws Exception {
         try (MockWebServer server = new MockWebServer()) {
             server.enqueue(new MockResponse().setHeader("Content-Type", "application/json").setBody("{\"message_id\":\"msg/id\",\"status\":\"scheduled\",\"scheduled_at\":\"2026-08-27T09:00:00Z\"}"));
             server.enqueue(new MockResponse().setHeader("Content-Type", "application/json").setBody("{\"message_id\":\"msg/id\",\"status\":\"canceled\",\"scheduled_at\":null}"));
+            server.enqueue(new MockResponse().setHeader("Content-Type", "application/json").setBody("{\"data\":{\"message_id\":\"msg/id\",\"status\":\"queued\",\"webhook_target_count\":1}}"));
             server.start();
 
             ApiClient api = Lettermint.api("api-token", server.url("/v1").toString());
             co.lettermint.models.api.RescheduleMessageRequest payload = new co.lettermint.models.api.RescheduleMessageRequest();
             payload.scheduledAt = "2026-08-27T09:00:00Z";
             assertEquals("scheduled", api.messages().reschedule("msg/id", payload).status);
             assertEquals("canceled", api.messages().cancel("msg/id").status);
+            assertEquals("queued", api.messages().process("msg/id").data.get("status"));
 
             RecordedRequest reschedule = server.takeRequest();
             assertEquals("PATCH", reschedule.getMethod());
@@ -165,6 +167,9 @@ void schedulesMessageChangesWithTypedResponses() throws Exception {
             RecordedRequest cancel = server.takeRequest();
             assertEquals("POST", cancel.getMethod());
             assertEquals("/v1/messages/msg%2Fid/cancel", cancel.getPath());
+            RecordedRequest process = server.takeRequest();
+            assertEquals("POST", process.getMethod());
+            assertEquals("/v1/messages/msg%2Fid/process", process.getPath());
         }
     }
 
@@ -270,6 +275,7 @@ void apiExposesDocumentedOperations() throws Exception {
         methods.put("message.show", api.messages().getClass().getMethod("retrieve", String.class));
         methods.put("rescheduleMessage", api.messages().getClass().getMethod("reschedule", String.class, co.lettermint.models.api.RescheduleMessageRequest.class));
         methods.put("cancelScheduledMessage", api.messages().getClass().getMethod("cancel", String.class));
+        methods.put("processInboundMessage", api.messages().getClass().getMethod("process", String.class));
         methods.put("message.events", api.messages().getClass().getMethod("events", String.class));
         methods.put("message.source", api.messages().getClass().getMethod("source", String.class));
         methods.put("message.html", api.messages().getClass().getMethod("html", String.class));