Add external plugin foundry-agent-canvas (#2321)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

.github/plugin/marketplace.json

@@ -550,6 +550,33 @@
       "description": "Give your AI agent full visibility into Power Automate cloud flows via the FlowStudio MCP server. Connect, debug, build, monitor health, and govern flows at scale — action-level inputs and outputs, not just status codes.",
       "version": "2.0.0"
     },
+    {
+      "name": "foundry-agent-canvas",
+      "description": "Interactive Copilot canvas for designing, configuring, testing, and deploying Microsoft Foundry hosted agents.",
+      "version": "1.0.0",
+      "author": {
+        "name": "Microsoft",
+        "url": "https://www.microsoft.com"
+      },
+      "repository": "https://github.com/microsoft/foundry-toolkit",
+      "homepage": "https://github.com/microsoft/foundry-toolkit",
+      "license": "MIT",
+      "keywords": [
+        "agent-builder",
+        "agent-inspector",
+        "azure-ai",
+        "foundry",
+        "hosted-agents",
+        "microsoft-foundry",
+        "canvas"
+      ],
+      "source": {
+        "source": "github",
+        "repo": "microsoft/foundry-toolkit",
+        "path": "foundry-agent-canvas",
+        "sha": "0d311e56508ac200ebb86586adbee9c7b8b0601f"
+      }
+    },
     {
       "name": "frontend-web-dev",
       "source": "plugins/frontend-web-dev",