feat: fit list tables to the terminal and write TSV when piped

Lists had no header, wrapped every row once a title was longer than
the terminal, and were space-padded when piped, so cut -f and awk -F'\t'
could not split them and empty cells collapsed.

terminal.Table now takes column specs and a Display. On a terminal it
prints an uppercase header, aligns columns two spaces apart and shrinks
flexible columns, widest first, to Streams.Width (the terminal, then
$COLUMNS, then 80), cutting by display width with "…". States use the
terminal's ANSI 16 colors, hex colors fall back to the 256-color palette
unless COLORTERM advertises 24-bit, and OSC 8 links appear only on the
first column, independently of color (TEA_HYPERLINKS=auto|always|never).
Piped tables are tab-separated without header, color or links, and times
are RFC3339 UTC instead of "about 2 hours ago".

terminal.View lays out single resources (title, badges, metadata, fields,
body, footer URL) and renders markdown bodies with glamour on a terminal
only (TEA_MARKDOWN=raw keeps them raw). Shared formatters cover relative
times, timestamps, sizes, durations and status icons.

In the app, writeTable and writeView are the new list and view writers:
a "Showing N of M …" context line, an empty-state message on stderr and
the next-page hint. writeList, writeItem and batch keep working and now
render through the new table: tab-separated when piped, truncated at the
widest column on a terminal, with headers for issue list and pr list.

Signed-off-by: bircni <bircni@icloud.com>

internal/terminal/time.go

@@ -0,0 +1,57 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package terminal
+
+import (
+	"fmt"
+	"time"
+)
+
+// RelativeTime describes t relative to now like gh: "less than a minute ago", "about 3 hours ago",
+// and "in about 2 months" for future times such as due dates.
+func RelativeTime(now, t time.Time) string {
+	d, prefix, suffix := now.Sub(t), "", " ago"
+	if d < 0 {
+		d, prefix, suffix = -d, "in ", ""
+	}
+	const day = 24 * time.Hour
+	var n time.Duration
+	var unit string
+	switch {
+	case d < time.Minute:
+		return prefix + "less than a minute" + suffix
+	case d < time.Hour:
+		n, unit = d/time.Minute, "minute"
+	case d < day:
+		n, unit = d/time.Hour, "hour"
+	case d < 30*day:
+		n, unit = d/day, "day"
+	case d < 365*day:
+		n, unit = d/(30*day), "month"
+	default:
+		n, unit = d/(365*day), "year"
+	}
+	return prefix + "about " + plural(int(n), unit) + suffix
+}
+
+// Timestamp formats t for scripts: RFC3339 in UTC at second precision.
+func Timestamp(t time.Time) string {
+	return t.UTC().Truncate(time.Second).Format(time.RFC3339)
+}
+
+// ParseTime parses an API timestamp, returning the zero time for an empty or malformed value.
+func ParseTime(raw string) time.Time {
+	t, err := time.Parse(time.RFC3339, raw)
+	if err != nil {
+		return time.Time{}
+	}
+	return t
+}
+
+func plural(n int, unit string) string {
+	if n == 1 {
+		return "1 " + unit
+	}
+	return fmt.Sprintf("%d %ss", n, unit)
+}