refactor(appserver): add canonical protocol constants

Author: loong10k

src/main/java/io/github/easy4j/codex/appserver/CodexAppServerProtocol.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2018-present, easy-4-java (https://github.com/easy-4-java).
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ */
+package io.github.easy4j.codex.appserver;
+
+/**
+ * Canonical method and notification names used by the Codex app-server
+ * integration. Keeping protocol strings in one place prevents the turn and
+ * generic-RPC transports from drifting apart.
+ */
+final class CodexAppServerProtocol {
+
+    static final String INITIALIZE = "initialize";
+    static final String INITIALIZED = "notifications/initialized";
+
+    static final String THREAD_START = "thread/start";
+    static final String THREAD_RESUME = "thread/resume";
+    static final String THREAD_LIST = "thread/list";
+    static final String THREAD_READ = "thread/read";
+    static final String THREAD_FORK = "thread/fork";
+    static final String THREAD_ARCHIVE = "thread/archive";
+    static final String THREAD_UNARCHIVE = "thread/unarchive";
+    static final String THREAD_DELETE = "thread/delete";
+
+    static final String TURN_START = "turn/start";
+    static final String TURN_STEER = "turn/steer";
+    static final String TURN_INTERRUPT = "turn/interrupt";
+
+    static final String TURN_STARTED = "turn/started";
+    static final String TURN_COMPLETED = "turn/completed";
+    static final String TURN_FAILED = "turn/failed";
+    static final String ITEM_STARTED = "item/started";
+    static final String ITEM_COMPLETED = "item/completed";
+    static final String AGENT_MESSAGE_DELTA = "item/agentMessage/delta";
+    static final String TOKEN_USAGE_UPDATED = "thread/tokenUsage/updated";
+    static final String ERROR = "error";
+
+    private CodexAppServerProtocol() {
+    }
+}