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/streams_test.go

@@ -0,0 +1,63 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package terminal
+
+import (
+	"bytes"
+	"context"
+	"io"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+// testPrompter returns a form prompter reading in and the buffer its forms render to.
+func testPrompter(in io.Reader) (*FormPrompter, *bytes.Buffer) {
+	rendered := &bytes.Buffer{}
+	return &FormPrompter{Streams: Streams{In: in, Out: &bytes.Buffer{}, ErrOut: rendered, InTTY: true, ErrTTY: true}}, rendered
+}
+
+// accessiblePrompter is testPrompter in accessible mode, which renders field titles as plain text.
+func accessiblePrompter(t *testing.T, input string) (*FormPrompter, *bytes.Buffer) {
+	t.Helper()
+	t.Setenv("TERM", "dumb")
+	return testPrompter(strings.NewReader(input))
+}
+
+func noEdit(context.Context, string) (Draft, error) { return Draft{}, nil }
+
+type fakePrompt struct{ inputs int }
+
+func (f *fakePrompt) Input(context.Context, string) (string, error) {
+	f.inputs++
+	return "provided", nil
+}
+func (f *fakePrompt) SecretInput(context.Context, string) (string, error) { return "", nil }
+func (f *fakePrompt) Confirm(context.Context, string) (bool, error)       { return false, nil }
+
+func TestPromptPolicy(t *testing.T) {
+	for _, tc := range []struct {
+		policy   Policy
+		streams  Streams
+		expected bool
+	}{
+		{Policy{Enabled: true}, Streams{InTTY: true, ErrTTY: true}, true},
+		{Policy{Enabled: true}, Streams{InTTY: true, OutTTY: true}, false},
+		{Policy{Enabled: true, NoInput: true}, Streams{InTTY: true, ErrTTY: true}, false},
+		{Policy{Enabled: true, Machine: true}, Streams{InTTY: true, ErrTTY: true}, false},
+		{Policy{Enabled: true, Machine: true, Interactive: true}, Streams{InTTY: true, ErrTTY: true}, true},
+	} {
+		require.Equal(t, tc.expected, tc.policy.CanPrompt(tc.streams))
+	}
+	prompt := &fakePrompt{}
+	value := "supplied"
+	asked, err := Require(context.Background(), &value, "title", Streams{}, Policy{}, prompt)
+	require.NoError(t, err)
+	require.False(t, asked)
+	require.Zero(t, prompt.inputs)
+	value = ""
+	_, err = Require(context.Background(), &value, "title", Streams{}, Policy{}, prompt)
+	require.ErrorContains(t, err, "--title")
+}