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/pull_form_test.go

@@ -0,0 +1,105 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package terminal
+
+import (
+	"context"
+	"errors"
+	"path/filepath"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestDefaultPullTitle(t *testing.T) {
+	for _, tc := range []struct{ in, want string }{
+		{"", ""},
+		{"feature", "Feature"},
+		{"fix-my-bug", "Fix My Bug"},
+		{"alice:add_login", "Add Login"},
+		{"über-fix", "Über Fix"},
+	} {
+		require.Equal(t, tc.want, DefaultPullTitle(tc.in), tc.in)
+	}
+}
+
+func TestPullFormMarksRequiredFields(t *testing.T) {
+	for _, tc := range []struct {
+		name, input   string
+		choices       PullFormChoices
+		want, without []string
+	}{
+		{
+			"without head", "n\nmain\nalice\nfeature\ny\nTitle\n",
+			PullFormChoices{},
+			[]string{"Target branch (required):", "Source branch (required):", "Issue title (required):"},
+			nil,
+		},
+		{
+			"with head", "n\n\n\n\n\nTitle\n",
+			PullFormChoices{Base: "main", HeadOwner: "alice", HeadBranch: "feature"},
+			[]string{"Source branch:", "Allow maintainers to push to the source branch:"},
+			[]string{"Source branch (required)"},
+		},
+		{"agit", "y\nmain\ntopic\nTitle\n", PullFormChoices{}, []string{"Topic branch (required):"}, nil},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			p, rendered := accessiblePrompter(t, tc.input)
+			tc.choices.EditBody = noEdit
+			_, err := p.CreatePull(context.Background(), tc.choices)
+			require.NoError(t, err)
+			for _, want := range tc.want {
+				require.Contains(t, rendered.String(), want)
+			}
+			for _, unwanted := range tc.without {
+				require.NotContains(t, rendered.String(), unwanted)
+			}
+		})
+	}
+}
+
+// stagedInput feeds one form's keystrokes per stage. A finished form's canceled read loop can still be inside Read,
+// and bubbletea drops the byte that Read returns. When a stage runs dry, the finished form's loop blocks first and
+// the next form's loop second, so the next stage is handed to that second reader and never to the stale one.
+type stagedInput struct {
+	mu     sync.Mutex
+	cur    string
+	stages []string
+	idle   int
+}
+
+func (s *stagedInput) Read(p []byte) (int, error) {
+	s.mu.Lock()
+	for s.cur == "" {
+		s.idle++
+		if s.idle < 2 || len(s.stages) == 0 {
+			s.mu.Unlock()
+			select {} // no more input for this reader; the loop is abandoned with its form
+		}
+		s.cur, s.stages, s.idle = s.stages[0], s.stages[1:], 0
+	}
+	p[0], s.cur = s.cur[0], s.cur[1:]
+	s.mu.Unlock()
+	return 1, nil
+}
+
+func TestCreatePullPreservesDraftOnEditorFailure(t *testing.T) {
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+	path := filepath.Join(t.TempDir(), "draft.md")
+	called := false
+	p, _ := testPrompter(&stagedInput{cur: "n\r", stages: []string{"main\ralice\rfeature\ry\r", "Title\r"}})
+	values, err := p.CreatePull(ctx, PullFormChoices{
+		BaseOwner: "alice", Base: "main", HeadOwner: "alice", HeadBranch: "feature",
+		EditBody: func(context.Context, string) (Draft, error) {
+			called = true
+			return Draft{Path: path, Body: "partial"}, errors.New("editor failed")
+		},
+	})
+	require.True(t, called)
+	require.ErrorContains(t, err, "editor failed")
+	require.Equal(t, path, values.Draft.Path)
+}