fix: improve delete worktree failure toast messages (#319)

- Show user-friendly guidance instead of raw git stderr when worktree
  deletion fails due to changed files, directing users to Force Delete.
- Extract toast message logic to reusable getDeleteWorktreeToastCopy
  function with comprehensive test coverage.

src/renderer/src/components/sidebar/DeleteWorktreeDialog.tsx

@@ -11,6 +11,7 @@ import { Button } from '@/components/ui/button'
 import { AlertTriangle, LoaderCircle, Trash2 } from 'lucide-react'
 import { useAppStore } from '@/store'
 import { toast } from 'sonner'
+import { getDeleteWorktreeToastCopy } from './delete-worktree-toast'
 
 const DeleteWorktreeDialog = React.memo(function DeleteWorktreeDialog() {
   const activeModal = useAppStore((s) => s.activeModal)
@@ -32,6 +33,7 @@ const DeleteWorktreeDialog = React.memo(function DeleteWorktreeDialog() {
   const isDeleting = deleteState?.isDeleting ?? false
   const deleteError = deleteState?.error ?? null
   const canForceDelete = deleteState?.canForceDelete ?? false
+  const worktreeName = worktree?.displayName ?? 'unknown'
 
   useEffect(() => {
     if (isOpen && worktreeId && !worktree && !isDeleting) {
@@ -66,8 +68,14 @@ const DeleteWorktreeDialog = React.memo(function DeleteWorktreeDialog() {
         .then((result) => {
           if (!result.ok) {
             const state = useAppStore.getState().deleteStateByWorktreeId[targetWorktreeId]
-            toast.error('Failed to delete worktree', {
-              description: result.error,
+            const toastCopy = getDeleteWorktreeToastCopy(
+              worktreeName,
+              state?.canForceDelete ?? false,
+              result.error
+            )
+            const showToast = toastCopy.isDestructive ? toast.error : toast.info
+            showToast(toastCopy.title, {
+              description: toastCopy.description,
               duration: 10000,
               action: state?.canForceDelete
                 ? {
@@ -97,7 +105,7 @@ const DeleteWorktreeDialog = React.memo(function DeleteWorktreeDialog() {
         })
       closeModal()
     },
-    [closeModal, removeWorktree, worktreeId]
+    [closeModal, removeWorktree, worktreeId, worktreeName]
   )
 
   return (

src/renderer/src/components/sidebar/delete-worktree-toast.test.ts

@@ -0,0 +1,20 @@
+import { describe, expect, it } from 'vitest'
+import { getDeleteWorktreeToastCopy } from './delete-worktree-toast'
+
+describe('getDeleteWorktreeToastCopy', () => {
+  it('uses direct guidance when force delete is available', () => {
+    expect(getDeleteWorktreeToastCopy('feature/foo', true, 'branch has changes')).toEqual({
+      title: 'Failed to delete worktree feature/foo',
+      description: 'It has changed files. Use Force Delete to delete it anyway.',
+      isDestructive: false
+    })
+  })
+
+  it('preserves the raw error when force delete is unavailable', () => {
+    expect(getDeleteWorktreeToastCopy('feature/foo', false, 'permission denied')).toEqual({
+      title: 'Failed to delete worktree feature/foo',
+      description: 'permission denied',
+      isDestructive: true
+    })
+  })
+})

src/renderer/src/components/sidebar/delete-worktree-toast.ts

@@ -0,0 +1,29 @@
+export type DeleteWorktreeToastCopy = {
+  title: string
+  description?: string
+  isDestructive: boolean
+}
+
+export function getDeleteWorktreeToastCopy(
+  worktreeName: string,
+  canForceDelete: boolean,
+  error: string
+): DeleteWorktreeToastCopy {
+  if (canForceDelete) {
+    return {
+      title: `Failed to delete worktree ${worktreeName}`,
+      description: 'It has changed files. Use Force Delete to delete it anyway.',
+      // Why: git commonly refuses the first delete when the worktree still has
+      // modified or untracked files. Showing raw stderr in a destructive toast
+      // made a normal cleanup step look like an Orca bug, so this common case
+      // gets a concise explanation plus the force-delete path instead.
+      isDestructive: false
+    }
+  }
+
+  return {
+    title: `Failed to delete worktree ${worktreeName}`,
+    description: error,
+    isDestructive: true
+  }
+}