Make the worktrees panel's detached-head text translatable

The recent repos menu is about to show the same text for a repo that has
no branch checked out. Hardcoding the English a second time would leave
translators with one of the two copies, so give the text a translation
key and take it from there in both places.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

pkg/gui/presentation/worktrees.go

@@ -49,7 +49,8 @@ func GetWorktreeDisplayString(tr *i18n.TranslationSet, worktree *models.Worktree
 	if worktree.Branch != "" {
 		branch = style.FgCyan.Sprint(worktree.Branch)
 	} else if worktree.Head != "" {
-		branch = style.FgYellow.Sprint("HEAD detached at " + utils.ShortHash(worktree.Head))
+		branch = style.FgYellow.Sprint(utils.ResolvePlaceholderString(
+			tr.HeadDetachedAt, map[string]string{"hash": utils.ShortHash(worktree.Head)}))
 	}
 	res = append(res, branch+mainWorktreeLabel(tr, worktree))
 	return res

pkg/gui/presentation/worktrees_test.go

@@ -14,6 +14,7 @@ func Test_GetWorktreeDisplayString(t *testing.T) {
 	tr := &i18n.TranslationSet{
 		MainWorktree:    "(main worktree)",
 		MissingWorktree: "(missing)",
+		HeadDetachedAt:  "HEAD detached at {{.hash}}",
 	}
 
 	scenarios := []struct {

pkg/i18n/english.go

@@ -718,6 +718,7 @@ type TranslationSet struct {
 	BranchNotFoundTitle                   string
 	BranchNotFoundPrompt                  string
 	BranchUnknown                         string
+	HeadDetachedAt                        string
 	DiscardChangeTitle                    string
 	DiscardChangePrompt                   string
 	DiscardLinesFromCommitTitle           string
@@ -1884,6 +1885,7 @@ func EnglishTranslationSet() *TranslationSet {
 		BranchNotFoundTitle:                      "Branch not found",
 		BranchNotFoundPrompt:                     "Branch not found. Create a new branch named",
 		BranchUnknown:                            "Branch unknown",
+		HeadDetachedAt:                           "HEAD detached at {{.hash}}",
 		DiscardChangeTitle:                       "Discard change",
 		DiscardChangePrompt:                      "Are you sure you want to discard this change (git reset)? It is irreversible.\nTo disable this dialogue set the config key of 'gui.skipDiscardChangeWarning' to true",
 		DiscardLinesFromCommitTitle:              "Discard lines from commit",