Function format_compact_session_elapsed 

pub fn format_compact_session_elapsed(secs: f64) -> String

Compact 8-char session-elapsed clock with a unit suffix (s/m/h) that scales as the run gets longer. The fractional precision shrinks step-by-step so the integer part stays bounded and the total width is constant — log rows column-align cleanly even when the suffix changes underneath them.

Layout (always 8 visible chars):

Magnitude	Example	Shape
0 – 9.99999s	1.23456s	1 int + 5 frac + s
10 – 99.9999s	99.1234s	2 int + 4 frac + s
100 – 999.999s	999.123s	3 int + 3 frac + s
16m – 1h	1.23456m	1 int + 5 frac + m
10m – 100m	99.1234m	2 int + 4 frac + m
100m – 1000m	999.123m	3 int + 3 frac + m
1h+	1.23456h	hours scaled
10h+	99.1234h
100h+	999.123h

Beyond 999.999h (≈ 41 days) the column widens, matching the format_elapsed_seconds precedent for runs longer than fit in 7 chars: the integer part grows, the fractional precision stays at 3.