feat(companion): add typed canvas RPC helpers for runtime clients

src/companion/runtimeClient.test.ts

@@ -224,4 +224,48 @@ describe('CompanionRuntimeClient', () => {
       client.disconnect();
     }
   });
+
+  it('supports canvas artifact lifecycle via typed helper methods', async () => {
+    if (!LISTEN_ALLOWED) {
+      return;
+    }
+
+    const client = new CompanionRuntimeClient({
+      url: `ws://127.0.0.1:${TEST_PORT}`,
+      token: TEST_TOKEN,
+    });
+
+    await client.connect();
+
+    try {
+      const sessionId = 'ws:companion-canvas';
+      const put = await client.putCanvasArtifact({
+        sessionId,
+        artifactId: 'artifact-1',
+        type: 'markdown',
+        title: 'Companion note',
+        content: { body: '# Hello' },
+        metadata: { source: 'runtime-client-test' },
+      });
+      expect(put.upserted).toBe(true);
+      expect(put.artifact.id).toBe('artifact-1');
+      expect(put.artifact.type).toBe('markdown');
+
+      const list = await client.listCanvasArtifacts(sessionId);
+      expect(list.artifacts.length).toBeGreaterThanOrEqual(1);
+      expect(list.artifacts.some((artifact) => artifact.id === 'artifact-1')).toBe(true);
+
+      const get = await client.getCanvasArtifact({ sessionId, artifactId: 'artifact-1' });
+      expect(get.artifact.id).toBe('artifact-1');
+      expect(get.artifact.title).toBe('Companion note');
+
+      const del = await client.deleteCanvasArtifact({ sessionId, artifactId: 'artifact-1' });
+      expect(del.deleted).toBe(true);
+
+      const clear = await client.clearCanvasArtifacts(sessionId);
+      expect(clear.cleared).toBe(0);
+    } finally {
+      client.disconnect();
+    }
+  });
 });