j127: fix TR_RACK_SHARE round-boundary dwell lock (bot.tick resets, tracker currentSince persists) - share path only

common_libs/gun_harness/virtual_bullets.nim

@@ -1202,8 +1202,13 @@ proc selectSharedGun*(t: var VirtualTracker, share: openArray[float],
 
   # Hold the incumbent through its dwell window (it is already one of the
   # admitted share guns). This is what keeps aim convergence; the deficit below
-  # is NOT advanced on a held tick.
-  if t.currentGun in guns and (tick - t.currentSince) < ActiveDwellTicks:
+  # is NOT advanced on a held tick. The `tick >= t.currentSince` guard is
+  # load-bearing: `bot.tick` RESETS to 0 each round while the tracker (and its
+  # `currentSince`) persists, so without it a negative elapsed would lock the
+  # round-1-end gun for every later round. The shipped ranking path keeps its
+  # own (single-gun-in-practice) dwell untouched.
+  if t.currentGun in guns and tick >= t.currentSince and
+     (tick - t.currentSince) < ActiveDwellTicks:
     return t.currentGun
 
   if t.shareDeficit.len != share.len: