Format list as an aligned table

The name is what the eye looks for, but it came last, behind a ragged
date column, so nothing lined up. Worse, colorRepoLine rebuilt the line
with strings.Fields and single spaces, which destroyed the alignment ls
had produced -- the output was aligned only when colour was off.

The listing line is now parsed properly instead of being split at the
size field: name, date and size come out as fields, the date is re-padded
to a fixed twelve columns so "Sep 28  2016" and "Jan  3 14:32" agree, and
the name leads in a column sized to the longest entry. Colour decorates
that layout without changing it, which a test now checks by stripping the
escapes and comparing. `list -a` shows archive sizes, which were parsed
and thrown away before.

An empty result says so instead of printing nothing, which was
indistinguishable from a failure, and the count line matches the rest of
mgsh. The pattern now filters on the repository name rather than the
whole listing line: matching the owner or the date was never intended and
`list 2016` quietly did it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

README.md

@@ -85,7 +85,7 @@ Run `help` for the full list. Highlights:
 | `log`                     | show the project log                           |
 | `edit [n]`                | interactive rebase of the last n commits       |
 | `clone [-a] <repo>`       | clone a repository (or archive) from the server |
-| `list [-a] [pattern]`     | list repositories on the server                |
+| `list [-a] [pattern]`     | list repositories on the server (`-a`: archives, with sizes) |
 | `show <repo>`             | show a repository log directly on the server   |
 | `archive [comment]`       | snapshot the server-side repo into `./archive` |
 | `init`                    | make a new repository from the current directory |
@@ -126,6 +126,23 @@ pushremote targets (in push order):
 Tokens are masked, so the output is safe to paste into a bug report.
 `config -k` prints just the setting names, one per line.
 
+### Listing the server
+
+`list` shows what is on the git server, name first and aligned, ordered by
+modification time — `push` touches the bare repository, so the most recently
+worked-on project sits closest to the prompt:
+
+```
+< src > list
+  Betaflight3.0.0  Sep 28  2016
+  website          Mar  3  2024
+  notes            Jan  3 14:32
+3 repositories
+```
+
+`list -a` lists the archives instead, with their sizes; a pattern filters by
+name (`list note`).
+
 ### Overview
 
 `overview` (or `status -a`) is the one view that needs mgsh: it is the only