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/color_test.go

@@ -0,0 +1,42 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package terminal
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestColorEnabledRespectsPreferenceAndEnvironment(t *testing.T) {
+	getenv := func(key string) string {
+		if key == "NO_COLOR" {
+			return "1"
+		}
+		return ""
+	}
+	require.True(t, ColorEnabled("always", false, nil))
+	require.False(t, ColorEnabled("never", true, nil))
+	require.True(t, ColorEnabled("auto", true, func(string) string { return "" }))
+	require.False(t, ColorEnabled("auto", false, func(string) string { return "" }))
+	require.False(t, ColorEnabled("auto", true, getenv))
+	require.True(t, ColorEnabled("always", true, getenv))
+	require.False(t, ColorEnabled("auto", true, func(key string) string { return map[string]string{"TERM": "dumb"}[key] }))
+}
+
+func TestColorizeAndEmphasis(t *testing.T) {
+	require.Equal(t, "bug", Colorize("ff0000", "bug", false))
+	require.Equal(t, "bug", Colorize("bad", "bug", true))
+	require.Equal(t, "\x1b[38;2;255;0;0mbug\x1b[0m", Colorize("#ff0000", "bug", true))
+	require.Equal(t, "open", Emphasis("open", false))
+	require.Equal(t, "\x1b[1mopen\x1b[0m", Emphasis("open", true))
+}
+
+func TestHyperlink(t *testing.T) {
+	require.Equal(t, "#7", Hyperlink("https://example.org/i/7", "#7", false))
+	require.Equal(t, "\x1b]8;;https://example.org/i/7\x1b\\#7\x1b]8;;\x1b\\", Hyperlink("https://example.org/i/7", "#7", true))
+	require.Equal(t, "#7", Hyperlink("", "#7", true))
+	require.Equal(t, "#7", Hyperlink("https://example.org/\x1b[2J", "#7", true))
+	require.Equal(t, "#7", Hyperlink("https://example.org/\u009b2J", "#7", true))
+}