Animation Smorgasbord (#15637)

Co-authored-by: Adam <2363879+adamdotdevin@users.noreply.github.com>

packages/storybook/.storybook/mocks/app/context/file.ts

@@ -0,0 +1,47 @@
+export type FileSelection = {
+  startLine: number
+  startChar: number
+  endLine: number
+  endChar: number
+}
+
+export type SelectedLineRange = {
+  start: number
+  end: number
+}
+
+export function selectionFromLines(selection?: SelectedLineRange): FileSelection | undefined {
+  if (!selection) return undefined
+  return {
+    startLine: selection.start,
+    startChar: 0,
+    endLine: selection.end,
+    endChar: 0,
+  }
+}
+
+const pool = [
+  "src/session/timeline.tsx",
+  "src/session/composer.tsx",
+  "src/components/prompt-input.tsx",
+  "src/components/session-todo-dock.tsx",
+  "README.md",
+]
+
+export function useFile() {
+  return {
+    tab(path: string) {
+      return `file:${path}`
+    },
+    pathFromTab(tab: string) {
+      if (!tab.startsWith("file:")) return ""
+      return tab.slice(5)
+    },
+    load: async () => undefined,
+    async searchFilesAndDirectories(query: string) {
+      const text = query.trim().toLowerCase()
+      if (!text) return pool
+      return pool.filter((path) => path.toLowerCase().includes(text))
+    },
+  }
+}