test(companion): add platform canvas lifecycle integration coverage

docs/plans/state.json

@@ -246,6 +246,17 @@
       ],
       "test_status": "pnpm test:run src/companion/runtimeClient.test.ts src/companion/platformClients.test.ts src/companion/platformClients.integration.test.ts + pnpm typecheck passing"
     },
+    "companion-platform-canvas-integration-coverage": {
+      "status": "completed",
+      "date": "2026-02-17",
+      "updated": "2026-02-17",
+      "summary": "Extended live integration coverage for `MacOSCompanionClient` to validate canvas artifact lifecycle (`put/get/list/delete/clear`) through platform wrappers against gateway handlers.",
+      "files_modified": [
+        "src/companion/platformClients.integration.test.ts",
+        "docs/plans/state.json"
+      ],
+      "test_status": "pnpm test:run src/companion/platformClients.integration.test.ts src/companion/runtimeClient.test.ts src/companion/platformClients.test.ts + pnpm typecheck passing"
+    },
     "browser-tools-activation-clarity": {
       "status": "completed",
       "date": "2026-02-17",

src/companion/platformClients.integration.test.ts

@@ -189,4 +189,42 @@ describe('platform clients integration', () => {
       client.disconnect();
     }
   });
+
+  it('macOS companion wrapper supports canvas artifact lifecycle', async () => {
+    if (!LISTEN_ALLOWED) {
+      return;
+    }
+
+    const runtime = createRuntime();
+    const client = new MacOSCompanionClient({ runtime, nodeId: 'macos-canvas-e2e' });
+    await client.connect();
+
+    try {
+      await client.register();
+
+      const sessionId = 'ws:platform-canvas-e2e';
+      const put = await client.putCanvasArtifact({
+        sessionId,
+        artifactId: 'mac-art-1',
+        type: 'note',
+        content: { text: 'hello from platform wrapper' },
+      });
+      expect(put.upserted).toBe(true);
+      expect(put.artifact.id).toBe('mac-art-1');
+
+      const list = await client.listCanvasArtifacts(sessionId);
+      expect(list.artifacts.some((artifact) => artifact.id === 'mac-art-1')).toBe(true);
+
+      const get = await client.getCanvasArtifact({ sessionId, artifactId: 'mac-art-1' });
+      expect(get.artifact.id).toBe('mac-art-1');
+
+      const del = await client.deleteCanvasArtifact({ sessionId, artifactId: 'mac-art-1' });
+      expect(del.deleted).toBe(true);
+
+      const clear = await client.clearCanvasArtifacts(sessionId);
+      expect(clear.cleared).toBe(0);
+    } finally {
+      client.disconnect();
+    }
+  });
 });