fix(ui): stat-tile overflow + visible build version

Two issues:

1. _StatTile in the Doctor page overflowed by ~6px on narrow
   widths because the Row containing the icon + label "AUDIT
   CHAIN" with letterSpacing=0.6 didn't fit in the ~90px
   constraint per tile (4 tiles in a Row sharing the page
   width). Fix: smaller icon (16→14), tighter gap, label wrapped
   in Flexible with TextOverflow.ellipsis, and the longest label
   shortened "AUDIT CHAIN" → "AUDIT" with the chain count moved
   to the subtitle.

2. The new redesign was easy to mistake for the previous build
   from the outside. Add a small monospaced version line right
   under "F∆I Studio" in the sidebar header:

       F∆I Studio
       v0.7.1 · warm-minimalism

   Self-identifying — "wrong build" is now visible without
   reading the about dialog.

Bumps fai_studio 0.7.0 -> 0.7.1.

Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>

pubspec.yaml

@@ -1,7 +1,7 @@
 name: fai_studio
 description: "F∆I Studio — desktop GUI for the F∆I hub"
 publish_to: 'none'
-version: 0.1.0
+version: 0.7.1
 
 environment:
   sdk: ^3.11.0-200.1.beta