chore(lint): enable no-floating-promises in all five ESLint scopes

A floated promise is invisible at review time — the call reads like an
awaited one minus four characters — and the unhandled rejection it
produces surfaces in a different test, in a different file, as a stack
pointing at SDK internals. In #1947 two un-held `callTool` calls made
`npm run ci` unpassable and took a full investigation to attribute; the
fix was two lines. `@typescript-eslint/no-floating-promises` catches the
class outright, so enable it at `error` everywhere.

The rule is type-aware and `tseslint.configs.recommended` is not, so each
scope's config gains a parser project. The four clients name their own
tsconfig projects (both of them — `src` and `__tests__`/`server` live in
different ones). The root scope has no tsconfig at all, so add
`tsconfig.lint.json`: a lint-only project covering `core/**`,
`test-servers/src/**`, and `vitest.shared.mts`, emitting nothing and
gating nothing. It sets `moduleResolution: bundler` deliberately — under
NodeNext `core/`'s extensionless imports fail to resolve, every import
degrades to `any`, and the rule silently stops seeing promises at all.

Measured surface, and the fixes:

- core (2) — `stream.close()` in two Hono `onAbort` listeners. Hono
  invokes subscribers with a bare `subscriber()`, so a promise returned
  from the listener is floated one layer up; `closeAbortedStream` owns
  the rejection where it can actually be owned.
- tui (5) — `handleDisconnect` had no catch of its own and its only
  caller is a key handler that cannot await, so a failing disconnect was
  a live unhandled rejection; it now surfaces the message the way
  `handleConnect` does. The rest are `void` at callers that genuinely
  cannot await, over callees that already own their failures.
- web (92) — 83 are Storybook `expect(...)`, which is instrumented and
  returns a promise, now awaited (`scrollAreaStoryAssertions` is async
  for the same reason). Two tests were asserting against a provider call
  they never awaited. `open(url)` in both web servers now warns instead
  of escaping a synchronous callback.
- cli, launcher — already clean.

Type-aware linting costs time: `clients/web`'s `eslint .` goes from ~8s
to ~19s, inside `validate`. Narrowing the loaded projects is the lever if
that needs reducing later; dropping the rule is not.

Closes #1959

Signed-off-by: cliffhall <cliff@futurescale.com>

clients/web/eslint.config.js

@@ -31,5 +31,32 @@ export default defineConfig([
       "react-refresh/only-export-components": "off",
     },
   },
+  {
+    // Type-aware pass for `no-floating-promises` (#1959). The rule needs type
+    // information, which `tseslint.configs.recommended` does not provide, and
+    // the parser needs a project that literally contains the linted file — so
+    // all four leaf projects are listed (`tsconfig.json` itself is a
+    // solution file with `files: []`, so it contains nothing).
+    //
+    // `.d.ts` is excluded: `vitest.shims.d.ts` is pulled in through a `types`
+    // reference rather than an `include`, so no project owns it, and a
+    // declaration file cannot float a promise anyway.
+    files: ["**/*.{ts,tsx}"],
+    ignores: ["**/*.d.ts"],
+    languageOptions: {
+      parserOptions: {
+        project: [
+          "./tsconfig.app.json",
+          "./tsconfig.node.json",
+          "./tsconfig.storybook.json",
+          "./tsconfig.test.json",
+        ],
+        tsconfigRootDir: import.meta.dirname,
+      },
+    },
+    rules: {
+      "@typescript-eslint/no-floating-promises": "error",
+    },
+  },
   ...storybook.configs["flat/recommended"],
 ]);

clients/web/server/server.ts

@@ -125,7 +125,13 @@ export async function startHonoServer(
         sandboxUrl ?? undefined,
       );
       if (config.autoOpen) {
-        open(url);
+        // A headless or otherwise browser-less host rejects here. The server
+        // is already listening and the banner above printed the URL, so warn
+        // and carry on rather than letting the rejection escape this
+        // synchronous listen callback and take the process down.
+        open(url).catch((err: unknown) => {
+          console.warn("Could not open a browser automatically:", err);
+        });
       }
     },
   );

clients/web/server/vite-hono-plugin.ts

@@ -114,7 +114,12 @@ export function honoMiddlewarePlugin(config: WebServerConfig): Plugin {
         );
 
         if (config.autoOpen) {
-          open(url);
+          // Same as the prod server: a browser-less host rejects, the dev
+          // server is already up, and the banner above printed the URL — so
+          // warn rather than let the rejection escape this sync helper.
+          open(url).catch((err: unknown) => {
+            console.warn("Could not open a browser automatically:", err);
+          });
         }
       };
 

clients/web/src/components/elements/CategoryBadge/CategoryBadge.stories.tsx

@@ -14,7 +14,7 @@ export const Transport: Story = {
   args: { category: "transport" },
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(canvas.getByText("transport")).toBeInTheDocument();
+    await expect(canvas.getByText("transport")).toBeInTheDocument();
   },
 };
 
@@ -22,6 +22,6 @@ export const Auth: Story = {
   args: { category: "auth" },
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(canvas.getByText("auth")).toBeInTheDocument();
+    await expect(canvas.getByText("auth")).toBeInTheDocument();
   },
 };

clients/web/src/components/elements/EmbeddableScrollArea/EmbeddableScrollArea.stories.tsx

@@ -24,7 +24,7 @@ export const FullSize: Story = {
   ),
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(canvas.getByText("Row 1")).toBeInTheDocument();
+    await expect(canvas.getByText("Row 1")).toBeInTheDocument();
   },
 };
 
@@ -38,6 +38,6 @@ export const Embedded: Story = {
   ),
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(canvas.getByText("Row 1")).toBeInTheDocument();
+    await expect(canvas.getByText("Row 1")).toBeInTheDocument();
   },
 };

clients/web/src/components/elements/ExpandToggle/ExpandToggle.stories.tsx

@@ -15,7 +15,9 @@ export const Collapsed: Story = {
   args: { expanded: false },
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(canvas.getByRole("button", { name: "Expand" })).toBeInTheDocument();
+    await expect(
+      canvas.getByRole("button", { name: "Expand" }),
+    ).toBeInTheDocument();
   },
 };
 
@@ -23,7 +25,7 @@ export const Expanded: Story = {
   args: { expanded: true },
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(
+    await expect(
       canvas.getByRole("button", { name: "Collapse" }),
     ).toBeInTheDocument();
   },

clients/web/src/components/elements/McpErrorBadge/McpErrorBadge.stories.tsx

@@ -14,7 +14,7 @@ export const HeaderMismatch: Story = {
   args: { code: -32020, name: "HeaderMismatch" },
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(canvas.getByText("-32020 HeaderMismatch")).toBeInTheDocument();
+    await expect(canvas.getByText("-32020 HeaderMismatch")).toBeInTheDocument();
   },
 };
 
@@ -22,7 +22,7 @@ export const MissingCapability: Story = {
   args: { code: -32021, name: "MissingRequiredClientCapability" },
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(
+    await expect(
       canvas.getByText("-32021 MissingRequiredClientCapability"),
     ).toBeInTheDocument();
   },
@@ -32,7 +32,7 @@ export const UnsupportedVersion: Story = {
   args: { code: -32022, name: "UnsupportedProtocolVersion" },
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(
+    await expect(
       canvas.getByText("-32022 UnsupportedProtocolVersion"),
     ).toBeInTheDocument();
   },
@@ -47,6 +47,6 @@ export const MethodNotFound: Story = {
   },
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(canvas.getByText("-32601 MethodNotFound")).toBeInTheDocument();
+    await expect(canvas.getByText("-32601 MethodNotFound")).toBeInTheDocument();
   },
 };

clients/web/src/components/elements/MessageDirectionBadge/MessageDirectionBadge.stories.tsx

@@ -14,7 +14,7 @@ export const Outgoing: Story = {
   args: { direction: "outgoing" },
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(canvas.getByText("client → server")).toBeInTheDocument();
+    await expect(canvas.getByText("client → server")).toBeInTheDocument();
   },
 };
 
@@ -22,6 +22,6 @@ export const Incoming: Story = {
   args: { direction: "incoming" },
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(canvas.getByText("server → client")).toBeInTheDocument();
+    await expect(canvas.getByText("server → client")).toBeInTheDocument();
   },
 };

clients/web/src/components/elements/MethodBadge/MethodBadge.stories.tsx

@@ -14,7 +14,7 @@ export const ToolsList: Story = {
   args: { method: "tools/list" },
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(canvas.getByText("tools/list")).toBeInTheDocument();
+    await expect(canvas.getByText("tools/list")).toBeInTheDocument();
   },
 };
 
@@ -22,6 +22,6 @@ export const TasksList: Story = {
   args: { method: "tasks/list" },
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(canvas.getByText("tasks/list")).toBeInTheDocument();
+    await expect(canvas.getByText("tasks/list")).toBeInTheDocument();
   },
 };

clients/web/src/components/elements/MonitoringToggle/MonitoringToggle.stories.tsx

@@ -15,7 +15,7 @@ export const Closed: Story = {
   args: { open: false },
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(
+    await expect(
       canvas.getByRole("button", { name: "Open monitoring sidebar" }),
     ).toBeInTheDocument();
   },
@@ -25,7 +25,7 @@ export const Open: Story = {
   args: { open: true },
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(
+    await expect(
       canvas.getByRole("button", { name: "Close monitoring sidebar" }),
     ).toBeInTheDocument();
   },

clients/web/src/components/elements/PinToggle/PinToggle.stories.tsx

@@ -15,7 +15,9 @@ export const Unpinned: Story = {
   args: { pinned: false },
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(canvas.getByRole("button", { name: "Pin" })).toBeInTheDocument();
+    await expect(
+      canvas.getByRole("button", { name: "Pin" }),
+    ).toBeInTheDocument();
   },
 };
 
@@ -23,6 +25,8 @@ export const Pinned: Story = {
   args: { pinned: true },
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(canvas.getByRole("button", { name: "Unpin" })).toBeInTheDocument();
+    await expect(
+      canvas.getByRole("button", { name: "Unpin" }),
+    ).toBeInTheDocument();
   },
 };

clients/web/src/components/elements/ReplayButton/ReplayButton.stories.tsx

@@ -14,6 +14,8 @@ type Story = StoryObj<typeof ReplayButton>;
 export const Default: Story = {
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(canvas.getByRole("button", { name: "Replay" })).toBeInTheDocument();
+    await expect(
+      canvas.getByRole("button", { name: "Replay" }),
+    ).toBeInTheDocument();
   },
 };

clients/web/src/components/elements/ResizeHandle/ResizeHandle.stories.tsx

@@ -44,7 +44,7 @@ export const Default: Story = {
   render: () => <ResizeDemo />,
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(
+    await expect(
       canvas.getByRole("separator", { name: "Resize demo panel" }),
     ).toBeInTheDocument();
   },

clients/web/src/components/elements/ScreenStage/ScreenStage.stories.tsx

@@ -48,7 +48,7 @@ export const FillsHostWidth: Story = {
     // sharper discriminator: a row flex leaves the layer full-width while
     // collapsing the child to the single "x").
     const layer = child.parentElement as HTMLElement;
-    expect(child.getBoundingClientRect().width).toBeCloseTo(
+    await expect(child.getBoundingClientRect().width).toBeCloseTo(
       layer.getBoundingClientRect().width,
       0,
     );
@@ -77,11 +77,11 @@ export const FillVariant: Story = {
     // Width still stretches onto the child (relative to the layer, as above);
     // the `fill` height comes from `bottom: 0` making the layer span the host.
     const layer = child.parentElement as HTMLElement;
-    expect(child.getBoundingClientRect().width).toBeCloseTo(
+    await expect(child.getBoundingClientRect().width).toBeCloseTo(
       layer.getBoundingClientRect().width,
       0,
     );
-    expect(layer.getBoundingClientRect().height).toBeGreaterThan(160 - 4);
+    await expect(layer.getBoundingClientRect().height).toBeGreaterThan(160 - 4);
   },
 };
 
@@ -97,6 +97,6 @@ export const Inactive: Story = {
   ),
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(canvas.queryByTestId("stage-child")).not.toBeInTheDocument();
+    await expect(canvas.queryByTestId("stage-child")).not.toBeInTheDocument();
   },
 };

clients/web/src/components/groups/ConnectionInfoContent/ConnectionInfoContent.stories.tsx

@@ -106,8 +106,10 @@ export const ServerInfoNotReported: Story = {
   },
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(canvas.queryByText("my-catalog-name")).not.toBeInTheDocument();
-    expect(canvas.getAllByText(SERVER_INFO_NOT_REPORTED_LABEL)).toHaveLength(2);
+    await expect(canvas.queryByText("my-catalog-name")).not.toBeInTheDocument();
+    await expect(
+      canvas.getAllByText(SERVER_INFO_NOT_REPORTED_LABEL),
+    ).toHaveLength(2);
   },
 };
 
@@ -187,11 +189,11 @@ export const WithOAuthIdToken: Story = {
   },
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(canvas.getByText("ID Token")).toBeInTheDocument();
+    await expect(canvas.getByText("ID Token")).toBeInTheDocument();
     // Only the ID token is a JWT here, so exactly one decode toggle is offered.
     await userEvent.click(
       canvas.getByRole("button", { name: "Decode JWT for ID Token" }),
     );
-    expect(canvas.getByText(/"sub": "user-42"/)).toBeInTheDocument();
+    await expect(canvas.getByText(/"sub": "user-42"/)).toBeInTheDocument();
   },
 };

clients/web/src/components/groups/LogStreamPanel/LogStreamPanel.stories.tsx

@@ -77,6 +77,6 @@ export const WithEntries: Story = {
   },
   // List scrollbar reserves a gutter and stays hidden when idle (#1474).
   play: async ({ canvasElement }) => {
-    expectScrollbarGutterIdleHidden(canvasElement);
+    await expectScrollbarGutterIdleHidden(canvasElement);
   },
 };

clients/web/src/components/groups/MessageDirectionFilter/MessageDirectionFilter.stories.tsx

@@ -31,10 +31,10 @@ export const AllVisible: Story = {
   args: { visibleDirections: { client: true, server: true } },
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(
+    await expect(
       canvas.getByRole("button", { name: "client → server" }),
     ).toBeInTheDocument();
-    expect(
+    await expect(
       canvas.getByRole("button", { name: "Deselect All" }),
     ).toBeInTheDocument();
   },

clients/web/src/components/groups/MonitoringControls/MonitoringControls.stories.tsx

@@ -20,7 +20,7 @@ type Story = StoryObj<typeof MonitoringControls>;
 export const AllTabs: Story = {
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(canvas.getByRole("radio", { name: "Logs" })).toBeChecked();
+    await expect(canvas.getByRole("radio", { name: "Logs" })).toBeChecked();
   },
 };
 
@@ -28,6 +28,6 @@ export const StdioServer: Story = {
   args: { tabs: ["Logs", "Protocol"], value: "Protocol" },
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(canvas.queryByRole("radio", { name: "Network" })).toBeNull();
+    await expect(canvas.queryByRole("radio", { name: "Network" })).toBeNull();
   },
 };

clients/web/src/components/groups/MonitoringScreen/MonitoringScreen.stories.tsx

@@ -47,7 +47,7 @@ type Story = StoryObj<typeof MonitoringScreen>;
 export const Logs: Story = {
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(canvas.getByText("Log stream")).toBeInTheDocument();
+    await expect(canvas.getByText("Log stream")).toBeInTheDocument();
   },
 };
 
@@ -55,6 +55,6 @@ export const Protocol: Story = {
   args: { value: "Protocol" },
   play: async ({ canvasElement }) => {
     const canvas = within(canvasElement);
-    expect(canvas.getByText("Request history")).toBeInTheDocument();
+    await expect(canvas.getByText("Request history")).toBeInTheDocument();
   },
 };

clients/web/src/components/groups/NetworkStreamPanel/NetworkStreamPanel.stories.tsx

@@ -50,7 +50,7 @@ export const WithEntries: Story = {
   args: { entries: sample },
   // List scrollbar reserves a gutter and stays hidden when idle (#1474).
   play: async ({ canvasElement }) => {
-    expectScrollbarGutterIdleHidden(canvasElement);
+    await expectScrollbarGutterIdleHidden(canvasElement);
   },
 };