🤖 fix: stabilize Sidebar/MultipleProjects story (#1148)

Fixes Storybook flakiness where **Sidebar > Multiple Projects** would
sometimes render a chat input depending on leftover localStorage
workspace selection.

Changes:
- Add an **App/Sidebar**-level decorator that clears the persisted
selected workspace before each story render.
- Refactor shared Storybook helpers by exporting and reusing
`createOnChatAdapter` / `createGitStatusExecutor` (removes duplicated
code in App demo/sidebar stories).

Validation:
- `make static-check`

---
_Generated with `mux` • Model: `openai:gpt-5.2` • Thinking: `xhigh`_

Author: ammar-agent

src/browser/stories/App.demo.stories.tsx

@@ -17,49 +17,22 @@ import {
   createStatusTool,
   createStaticChatHandler,
   createStreamingChatHandler,
-  createGitStatusOutput,
   type GitStatusFixture,
 } from "./mockFactory";
-import { selectWorkspace, setWorkspaceInput, setWorkspaceModel } from "./storyHelpers";
+import {
+  createGitStatusExecutor,
+  createOnChatAdapter,
+  type ChatHandler,
+  selectWorkspace,
+  setWorkspaceInput,
+  setWorkspaceModel,
+} from "./storyHelpers";
 import { createMockORPCClient } from "../../../.storybook/mocks/orpc";
-import type { WorkspaceChatMessage } from "@/common/orpc/types";
-
 export default {
   ...appMeta,
   title: "App/Demo",
 };
 
-type ChatHandler = (callback: (event: WorkspaceChatMessage) => void) => () => void;
-
-/** Adapts callback-based chat handlers to ORPC onChat format */
-function createOnChatAdapter(chatHandlers: Map<string, ChatHandler>) {
-  return (workspaceId: string, emit: (msg: WorkspaceChatMessage) => void) => {
-    const handler = chatHandlers.get(workspaceId);
-    if (handler) {
-      return handler(emit);
-    }
-    queueMicrotask(() => emit({ type: "caught-up" }));
-    return undefined;
-  };
-}
-
-/** Creates an executeBash function that returns git status output for workspaces */
-function createGitStatusExecutor(gitStatus: Map<string, GitStatusFixture>) {
-  return (workspaceId: string, script: string) => {
-    if (script.includes("git status") || script.includes("git show-branch")) {
-      const status = gitStatus.get(workspaceId) ?? {};
-      const output = createGitStatusOutput(status);
-      return Promise.resolve({ success: true as const, output, exitCode: 0, wall_duration_ms: 50 });
-    }
-    return Promise.resolve({
-      success: true as const,
-      output: "",
-      exitCode: 0,
-      wall_duration_ms: 0,
-    });
-  };
-}
-
 /**
  * Comprehensive story showing all sidebar indicators and chat features.
  *

src/browser/stories/App.sidebar.stories.tsx

@@ -15,33 +15,29 @@ import {
   createGitStatusOutput,
   type GitStatusFixture,
 } from "./mockFactory";
-import { expandProjects } from "./storyHelpers";
+import {
+  clearWorkspaceSelection,
+  createOnChatAdapter,
+  type ChatHandler,
+  expandProjects,
+} from "./storyHelpers";
 import { GIT_STATUS_INDICATOR_MODE_KEY } from "@/common/constants/storage";
 import { within, userEvent, waitFor } from "@storybook/test";
 
 import { createMockORPCClient } from "../../../.storybook/mocks/orpc";
 
-import type { WorkspaceChatMessage } from "@/common/orpc/types";
-
 export default {
   ...appMeta,
   title: "App/Sidebar",
+  decorators: [
+    (Story: () => JSX.Element) => {
+      // Sidebar stories are about list organization; keep the main panel unselected.
+      clearWorkspaceSelection();
+      return <Story />;
+    },
+  ],
 };
 
-type ChatHandler = (callback: (event: WorkspaceChatMessage) => void) => () => void;
-
-/** Adapts callback-based chat handlers to ORPC onChat format */
-function createOnChatAdapter(chatHandlers: Map<string, ChatHandler>) {
-  return (workspaceId: string, emit: (msg: WorkspaceChatMessage) => void) => {
-    const handler = chatHandlers.get(workspaceId);
-    if (handler) {
-      return handler(emit);
-    }
-    queueMicrotask(() => emit({ type: "caught-up" }));
-    return undefined;
-  };
-}
-
 /**
  * Creates an executeBash function that returns deterministic git outputs for Storybook.
  *

src/browser/stories/storyHelpers.ts

@@ -45,6 +45,11 @@ export function selectWorkspace(workspace: FrontendWorkspaceMetadata): void {
   );
 }
 
+/** Clear workspace selection from localStorage (for sidebar-focused stories) */
+export function clearWorkspaceSelection(): void {
+  localStorage.removeItem(SELECTED_WORKSPACE_KEY);
+}
+
 /** Set input text for a workspace */
 export function setWorkspaceInput(workspaceId: string, text: string): void {
   localStorage.setItem(getInputKey(workspaceId), text);
@@ -98,7 +103,7 @@ export function createReview(
 // ═══════════════════════════════════════════════════════════════════════════════
 
 /** Creates an executeBash function that returns git status output for workspaces */
-function createGitStatusExecutor(gitStatus?: Map<string, GitStatusFixture>) {
+export function createGitStatusExecutor(gitStatus?: Map<string, GitStatusFixture>) {
   return (workspaceId: string, script: string) => {
     if (script.includes("git status") || script.includes("git show-branch")) {
       const status = gitStatus?.get(workspaceId) ?? {};
@@ -118,10 +123,10 @@ function createGitStatusExecutor(gitStatus?: Map<string, GitStatusFixture>) {
 // CHAT HANDLER ADAPTER
 // ═══════════════════════════════════════════════════════════════════════════════
 
-type ChatHandler = (callback: (event: WorkspaceChatMessage) => void) => () => void;
+export type ChatHandler = (callback: (event: WorkspaceChatMessage) => void) => () => void;
 
 /** Adapts callback-based chat handlers to ORPC onChat format */
-function createOnChatAdapter(chatHandlers: Map<string, ChatHandler>) {
+export function createOnChatAdapter(chatHandlers: Map<string, ChatHandler>) {
   return (workspaceId: string, emit: (msg: WorkspaceChatMessage) => void) => {
     const handler = chatHandlers.get(workspaceId);
     if (handler) {