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/view.go

@@ -0,0 +1,127 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package terminal
+
+import (
+	"strings"
+
+	"github.com/mattn/go-runewidth"
+)
+
+// Field is one labeled fact in a View.
+type Field struct {
+	Label string
+	// Value is plain text. Cells, when set, replace it with styled values joined by commas, such
+	// as colored labels.
+	Value string
+	Cells []Cell
+	// TTYOnly and PipedOnly restrict the field to one kind of output, like table columns.
+	TTYOnly, PipedOnly bool
+}
+
+// text returns the field's safe value, styled for d when it is made of cells.
+func (f Field) text(d Display) string {
+	if len(f.Cells) == 0 {
+		return SafeLine(f.Value)
+	}
+	values := make([]string, len(f.Cells))
+	for i, cell := range f.Cells {
+		values[i] = SafeLine(cell.Text)
+		if d.TTY {
+			values[i] = cell.style(values[i], d, false)
+		}
+	}
+	return strings.Join(values, ", ")
+}
+
+// View is one resource for human readers, such as an issue, a release or a repository.
+//
+// On a TTY it shows the bold title with its muted ID, a line of badges and muted metadata, the
+// aligned non-empty fields, the body (markdown rendered when the display allows), and the footer
+// "View this <kind> on Gitea: <url>". Otherwise it writes "key:\tvalue" lines for the title, the
+// fields and the URL, then "--" and the raw body, for scripts.
+type View struct {
+	Title, ID string
+	// Badges, such as the state, start the line under the title; Meta completes it, for example
+	// "alice opened about 2 hours ago • 2 comments".
+	Badges []Cell
+	Meta   string
+	Fields []Field
+	Body   string
+	// Kind names the resource in the footer, such as "issue".
+	Kind, URL string
+}
+
+// Render formats the view for d. All server text is sanitized.
+func (v View) Render(d Display) string {
+	var b strings.Builder
+	if !d.TTY {
+		if v.Title != "" {
+			b.WriteString("title:\t" + SafeLine(v.Title) + "\n")
+		}
+		for _, field := range v.Fields {
+			if !field.TTYOnly {
+				b.WriteString(strings.ToLower(SafeLine(field.Label)) + ":\t" + field.text(d) + "\n")
+			}
+		}
+		if v.URL != "" {
+			b.WriteString("url:\t" + SafeLine(v.URL) + "\n")
+		}
+		body := SafeText(v.Body)
+		b.WriteString("--\n" + body)
+		if !strings.HasSuffix(body, "\n") {
+			b.WriteByte('\n')
+		}
+		return b.String()
+	}
+
+	muted := func(text string) string { return Cell{Muted: true}.style(text, d, false) }
+	b.WriteString(Cell{Bold: true}.style(SafeLine(v.Title), d, false))
+	if v.ID != "" {
+		b.WriteString(" " + muted(SafeLine(v.ID)))
+	}
+	b.WriteByte('\n')
+	var summary []string
+	for _, badge := range v.Badges {
+		summary = append(summary, badge.style(SafeLine(badge.Text), d, false))
+	}
+	if meta := SafeLine(v.Meta); meta != "" {
+		summary = append(summary, muted(meta))
+	}
+	if len(summary) > 0 {
+		b.WriteString(strings.Join(summary, " • ") + "\n")
+	}
+
+	var fields []Field
+	labelWidth := 0
+	for _, field := range v.Fields {
+		if !field.PipedOnly && (field.Value != "" || len(field.Cells) > 0) {
+			fields = append(fields, field)
+			labelWidth = max(labelWidth, runewidth.StringWidth(SafeLine(field.Label)))
+		}
+	}
+	for _, field := range fields {
+		label := SafeLine(field.Label) + ":"
+		b.WriteString(Cell{Bold: true}.style(label, d, false) + strings.Repeat(" ", labelWidth+2-runewidth.StringWidth(label)) + field.text(d) + "\n")
+	}
+
+	body := strings.TrimSpace(v.Body)
+	switch {
+	case body == "":
+		body = muted("No description provided")
+	case d.Markdown:
+		body = Markdown(body, d)
+	default:
+		body = SafeText(body)
+	}
+	b.WriteString("\n" + body + "\n")
+	if v.URL != "" {
+		kind := "View on Gitea: "
+		if v.Kind != "" {
+			kind = "View this " + v.Kind + " on Gitea: "
+		}
+		b.WriteString("\n" + muted(kind+SafeLine(v.URL)) + "\n")
+	}
+	return b.String()
+}