Fixes for M-02 to M-14, G-01 to G-14, K-02 to K-04, X-04 to X-14, not yet reviewed

Committed before review so Windows and WSL builds can start.
Each fix was tested and mutation-checked here; the codex review
of each item is still to come, so tasks/BUGS.md stays unticked.

M-02 is mid-review: round 1 findings are fixed (apps/ely-mark/src/tally.rs).
K-01 stays deferred. The ElyMark window test mark-outside.sh failed
once at its crash-recovery step in the last run; not yet looked into.

apps/ely-tree/src/running.rs

@@ -154,6 +154,9 @@ impl Stop {
     }
 }
 
+/// Only Unix stops Git; elsewhere no stop shows.
+pub const STOPS: bool = cfg!(unix);
+
 /// Its own session: the group is Git and its helpers.
 #[cfg(unix)]
 fn terminate(pid: u32) -> io::Result<()> {