refactor: reuse the existing service and rendering helpers

services.IsNotFound replaces the hand-rolled 404 checks, convertPage
the copied page conversions and lastPathNumber the comment's own
number parser. The List wrappers around ListPage of releases,
branches, wiki pages, secrets and variables go, pull request filters
resolve milestones through Milestones.FindOne like issues, and
localFlagsChanged, boolOrder, Cell.Render, stateBadge and dueText
replace their copies.

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

internal/terminal/table.go

@@ -83,6 +83,9 @@ func (c Cell) style(text string, d Display, link bool) string {
 	return Hyperlink(c.Link, text, link && d.Links)
 }
 
+// Render styles the cell's text outside a table: its color, muted or bold, without a link.
+func (c Cell) Render(d Display) string { return c.style(SafeLine(c.Text), d, false) }
+
 // Table renders rows under columns; rows may have more cells than there are columns. On a TTY it
 // prints an uppercase header row when any column has a header, aligns columns two spaces apart,
 // and shrinks Flex columns until rows fit the display width. Otherwise it writes one line of