Breathing pulse: 3x faster (0.15s -> 0.05s per frame)

YuKu: 'the breathing is super slow'. Frame interval down from 150ms
to 50ms (~7fps -> ~20fps pulse). Same change in the vendored
lib/ui-block.sh helper for consistency.

lib/common.sh

@@ -141,7 +141,7 @@ ui_quiet_run() {
             fi
         fi
         f=$(( f + 1 ))
-        sleep 0.15
+        sleep 0.05
     done
 
     local rc=0

lib/ui-block.sh

@@ -55,7 +55,7 @@ _ub_busy_loop() {
       else
         printf '\r[%s] %s' "$i" "$_UB_MSG" >&"$_UB_FD"
       fi
-      sleep 0.08 || return 0
+      sleep 0.05 || return 0
     done
   done
 }