fix(server-ai): check _ldMeta.enabled before returning enabled graph

Addresses PR feedback: when _ldMeta.enabled is false, agentGraph() was
still returning { enabled: true, graph } despite the AgentGraphDefinition
documenting that enabled graphs are always true. Now returns disabled early
if the flag is explicitly disabled.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: jsonbailey

packages/sdk/server-ai/__tests__/agentGraph.test.ts

@@ -55,6 +55,20 @@ function makeAgentFlagValue(key: string, enabled = true) {
 // agentGraph – disabled / validation failures
 // ---------------------------------------------------------------------------
 
+it('returns { enabled: false } when _ldMeta.enabled is false', async () => {
+  const client = makeClient();
+  mockVariation.mockResolvedValueOnce({ _ldMeta: { enabled: false }, root: 'root' });
+  const result = await client.agentGraph('my-graph', testContext);
+  expect(result.enabled).toBe(false);
+});
+
+it('logs debug when graph is disabled via _ldMeta.enabled', async () => {
+  const client = makeClient();
+  mockVariation.mockResolvedValueOnce({ _ldMeta: { enabled: false }, root: 'root' });
+  await client.agentGraph('my-graph', testContext);
+  expect(mockDebug).toHaveBeenCalledWith(expect.stringContaining('disabled'));
+});
+
 it('returns { enabled: false } when graph flag has no root', async () => {
   const client = makeClient();
   mockVariation.mockResolvedValueOnce({ root: '' }); // no root

packages/sdk/server-ai/src/LDAIClientImpl.ts

@@ -408,7 +408,13 @@ export class LDAIClientImpl implements LDAIClient {
       defaultGraphValue,
     )) as LDAgentGraphFlagValue;
 
-    // Step 2: Validate - graph must be fetchable (has a root)
+    // Step 2: Validate - graph must be enabled and have a root
+    // eslint-disable-next-line no-underscore-dangle
+    if (graphFlagValue._ldMeta?.enabled === false) {
+      this._logger?.debug(`agentGraph: graph "${graphKey}" is disabled.`);
+      return disabled;
+    }
+
     if (!graphFlagValue.root) {
       this._logger?.debug(`agentGraph: graph "${graphKey}" is not fetchable or has no root node.`);
       return disabled;