refactor: add terminal output and forms package (#1124)

- `internal/terminal`: streams and the prompting policy, interactive forms (issue, PR, review, merge, milestone), editor / pager / browser launching, JSON and `--jq` output.
- An aligned table renderer and a record renderer for human output; both strip control and escape characters from server-supplied text so titles and bodies cannot inject terminal sequences.

Reviewed-on: https://gitea.com/gitea/tea/pulls/1124
Reviewed-by: TheFox0x7 <95654+thefox0x7@noreply.gitea.com>

internal/terminal/editor_test.go

@@ -0,0 +1,129 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package terminal
+
+import (
+	"bytes"
+	"context"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/kballard/go-shellquote"
+	"github.com/stretchr/testify/require"
+)
+
+func TestEditorRetainsPrivateDraftAfterSuccessAndFailure(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.Skip("editor fixture uses a POSIX executable")
+	}
+	for _, fail := range []bool{false, true} {
+		directory := t.TempDir()
+		program := filepath.Join(directory, "editor with spaces")
+		text := "#!/bin/sh\nprintf 'edited draft' > \"$1\"\nchmod 644 \"$1\"\nprintf 'editor diagnostic'\n"
+		if fail {
+			text += "exit 7\n"
+		}
+		require.NoError(t, os.WriteFile(program, []byte(text), 0o700))
+		out, diagnostics := &bytes.Buffer{}, &bytes.Buffer{}
+		draft, err := (SystemEditor{Directory: directory, Streams: Streams{Out: out, ErrOut: diagnostics}}).Edit(context.Background(), shellquote.Join(program), "initial text")
+		if fail {
+			require.Error(t, err)
+		} else {
+			require.NoError(t, err)
+			require.Equal(t, "edited draft", draft.Body)
+		}
+		data, readErr := os.ReadFile(draft.Path)
+		require.NoError(t, readErr)
+		require.Equal(t, "edited draft", string(data))
+		info, statErr := os.Stat(draft.Path)
+		require.NoError(t, statErr)
+		require.Equal(t, os.FileMode(0o600), info.Mode().Perm())
+		require.Empty(t, out.String())
+		require.Equal(t, "editor diagnostic", diagnostics.String())
+	}
+}
+
+func TestEditorCanceledBeforeLaunchDoesNotCreateDraft(t *testing.T) {
+	directory := t.TempDir()
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+	draft, err := (SystemEditor{Directory: directory}).Edit(ctx, "editor", "text")
+	require.ErrorIs(t, err, context.Canceled)
+	require.Empty(t, draft.Path)
+	files, err := os.ReadDir(directory)
+	require.NoError(t, err)
+	require.Empty(t, files)
+}
+
+func TestEditorIsNotKilledOnCancellation(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.Skip("editor fixture uses a POSIX executable")
+	}
+	directory := t.TempDir()
+	program := filepath.Join(directory, "slow-editor")
+	require.NoError(t, os.WriteFile(program, []byte("#!/bin/sh\nsleep 0.3\necho finished > \"$1\"\n"), 0o700))
+	ctx, cancel := context.WithCancel(context.Background())
+	time.AfterFunc(50*time.Millisecond, cancel)
+	draft, err := (SystemEditor{Directory: directory}).Edit(ctx, shellquote.Join(program), "text")
+	require.ErrorIs(t, err, context.Canceled)
+	data, err := os.ReadFile(draft.Path)
+	require.NoError(t, err)
+	require.Equal(t, "finished\n", string(data))
+}
+
+func TestEditorRecoversOriginalInputWhenBufferIsRemoved(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		t.Skip("editor fixture uses a POSIX executable")
+	}
+	directory := t.TempDir()
+	program := filepath.Join(directory, "remove-editor")
+	require.NoError(t, os.WriteFile(program, []byte("#!/bin/sh\nrm \"$1\"\nexit 1\n"), 0o700))
+	draft, err := (SystemEditor{Directory: directory}).Edit(context.Background(), shellquote.Join(program), "original draft")
+	require.ErrorContains(t, err, "original input was saved separately")
+	data, err := os.ReadFile(draft.Path)
+	require.NoError(t, err)
+	require.Equal(t, "original draft", string(data))
+	info, err := os.Stat(draft.Path)
+	require.NoError(t, err)
+	require.Equal(t, os.FileMode(0o600), info.Mode().Perm())
+}
+
+func TestCommandArgsKeepsUnquotedExecutablePaths(t *testing.T) {
+	name := `editor with spaces\and backslash`
+	if runtime.GOOS == "windows" {
+		name = "editor with spaces.bat"
+	}
+	program := filepath.Join(t.TempDir(), name)
+	require.NoError(t, os.WriteFile(program, []byte("#!/bin/sh\n"), 0o700))
+	for _, tc := range []struct {
+		command string
+		want    []string
+	}{
+		{program, []string{program}},
+		{shellquote.Join(program) + " --wait", []string{program, "--wait"}},
+		{"code --wait", []string{"code", "--wait"}},
+	} {
+		args, ok := commandArgs(tc.command)
+		require.True(t, ok, tc.command)
+		require.Equal(t, tc.want, args)
+	}
+	for _, command := range []string{"", `"unterminated`} {
+		_, ok := commandArgs(command)
+		require.False(t, ok, command)
+	}
+}
+
+func TestSubprocessFailuresKeepTheirCause(t *testing.T) {
+	const missing = "tea-test-missing-command"
+	streams := Streams{Out: &bytes.Buffer{}, ErrOut: &bytes.Buffer{}}
+	require.ErrorIs(t, (SystemEditor{Streams: streams}).EditPath(context.Background(), missing, filepath.Join(t.TempDir(), "draft")), exec.ErrNotFound)
+	require.ErrorIs(t, (SystemPager{}).Page(context.Background(), missing, strings.NewReader("text\n"), streams), exec.ErrNotFound)
+	require.ErrorIs(t, (SystemBrowser{ErrOut: streams.ErrOut}).Open(context.Background(), "https://example.org", missing), exec.ErrNotFound)
+	require.ErrorContains(t, (SystemBrowser{}).Open(context.Background(), "https://example.org", "never"), "browser opening is disabled")
+}