Add opt-in multi-line real-time build status display

[orgads]

Add an opt-in -m status mode that shows currently running edges in a multi-line real-time status area on ANSI-capable terminals, while preserving the existing single-line output when the flag is not used.

Each status line shows the edge sequence number, description, and elapsed time. The multiline display is capped to the terminal height and 8 rows, and its width is clamped to 60 columns. Long job titles are trimmed from the left so the right side remains visible.

The last finished edge is kept as a temporary line above the active status block, overwritten by the next completion. Error output and command output are printed cleanly after clearing the status area.

Key changes:

• Add -m to enable multiline status explicitly.
• Keep default output unchanged when -m is not given.
• Add 100ms timeout to ppoll/pselect/IOCP so DoWork() returns periodically and refreshes status via Report().
• Detect terminal dimensions to cap status lines at min(rows - 1, 8).
• Clamp multiline width to 60 columns and trim long titles from the left.
• Track each edge's start order via Edge::sequence_ for per-line numbering.
• Overwrite the display block in place to reduce flicker.
• Show ... and N more when running edges exceed the display limit.

Fixes #111.

[orgads]

It is very slow on Windows. I'll see if I can improve it. Changing to draft for now.