Add a test for pasting text into the commit description

It checks that the text goes in at the cursor, and that a tab turns
into spaces instead of switching to the summary.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

pkg/integration/tests/commit/paste_into_commit_description.go

@@ -0,0 +1,31 @@
+package commit
+
+import (
+	"github.com/jesseduffield/lazygit/pkg/config"
+	. "github.com/jesseduffield/lazygit/pkg/integration/components"
+)
+
+var PasteIntoCommitDescription = NewIntegrationTest(NewIntegrationTestArgs{
+	Description:  "Paste text into the commit description with the terminal's paste command",
+	ExtraCmdArgs: []string{},
+	Skip:         false,
+	SetupConfig:  func(config *config.AppConfig) {},
+	SetupRepo: func(shell *Shell) {
+		shell.CreateFileAndAdd("file", "file content")
+	},
+	Run: func(t *TestDriver, keys config.KeybindingConfig) {
+		t.Views().Files().
+			Focus().
+			Press(keys.Files.CommitChanges)
+
+		t.ExpectPopup().CommitMessagePanel().
+			Type("subject").
+			SwitchToDescription().
+			Type("last line").
+			GoToBeginning().
+			Paste("first line\n\tindented line\n").
+			Content(Equals("first line\n    indented line\nlast line"))
+
+		t.ExpectPopup().CommitDescriptionPanel()
+	},
+})

pkg/integration/tests/test_list.go

@@ -186,6 +186,7 @@ var tests = []*components.IntegrationTest{
 	commit.PasteCommitMessage,
 	commit.PasteCommitMessageOverExisting,
 	commit.PasteCommitMessageWithHardLineBreaks,
+	commit.PasteIntoCommitDescription,
 	commit.PreserveCommitMessage,
 	commit.PreserveCommitMessageWhitespace,
 	commit.ResetAuthor,