polish(repo): color mirror list columns like trail list

Trail-list-style static coloring on `repo mirror list` and
`repo mirror get <owner/repo>`: yellow headers, cyan clusters/access,
gray private, status by lifecycle (ready/available green,
processing/mixed yellow, failed red, suspended magenta). Plain stdout —
no alt-screen TUI — so the table stays mouse-selectable and copyable.

Style is decided against the final writer before flushThroughPager
swaps in its buffer (a buffer never looks like a TTY); cells are
pre-colored and the shared renderer measures widths ANSI-agnostically,
so color never shifts columns and `less -R` keeps it in the paged
view. Pipes, --json, and NO_COLOR see bare text unchanged.

The list RunE moved to runRepoMirrorList/-Page/-Walk with a
repoMirrorListOpts carrier — maintidx flagged the constructor once the
styling wiring landed on top.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Entire-Checkpoint: 01KY75XDVZMS76XYGQG4QMQVNY

Author: gtrrz-victor