fix: show devcontainer Delete menu for failed/error states

The three-dot menu (containing Delete) was gated behind
showDevcontainerControls which requires both a subAgent AND a
container reference. When a devcontainer fails (e.g. exit status 1),
the container and/or subAgent may be missing, hiding the menu entirely.

Decouple the Delete menu from showDevcontainerControls so it renders
whenever the devcontainer is not in a transitioning state (starting,
stopping, deleting). The delete API only needs parentAgent.id and
devcontainer.id, so no subAgent or container is required.

Fixes #23754

site/src/modules/resources/AgentDevcontainerCard.stories.tsx

@@ -1,5 +1,5 @@
 import type { Meta, StoryObj } from "@storybook/react-vite";
-import { screen, spyOn, userEvent, within } from "storybook/test";
+import { expect, screen, spyOn, userEvent, within } from "storybook/test";
 import { API } from "#/api/api";
 import { getPreferredProxy } from "#/contexts/ProxyContext";
 import { chromatic } from "#/testHelpers/chromatic";
@@ -57,6 +57,13 @@ export const HasError: Story = {
 			agent: undefined,
 		},
 	},
+	play: async ({ canvasElement }) => {
+		const canvas = within(canvasElement);
+		const moreActionsButton = canvas.getByRole("button", {
+			name: "Dev Container actions",
+		});
+		expect(moreActionsButton).toBeVisible();
+	},
 };
 
 export const NoPorts: Story = {};
@@ -123,6 +130,13 @@ export const NoContainerOrSubAgent: Story = {
 		},
 		subAgents: [],
 	},
+	play: async ({ canvasElement }) => {
+		const canvas = within(canvasElement);
+		const moreActionsButton = canvas.getByRole("button", {
+			name: "Dev Container actions",
+		});
+		expect(moreActionsButton).toBeVisible();
+	},
 };
 
 export const NoContainerOrAgentOrName: Story = {

site/src/modules/resources/AgentDevcontainerCard.tsx

@@ -274,7 +274,7 @@ export const AgentDevcontainerCard: FC<AgentDevcontainerCardProps> = ({
 							/>
 						)}
 
-					{showDevcontainerControls && (
+					{!isTransitioning && (
 						<AgentDevcontainerMoreActions
 							deleteDevContainer={deleteDevcontainerMutation.mutate}
 						/>