fix(PPO_Bot): radar lock — use enemy_tracker width-lock, fix arctan2 arg order

Three bugs caused the radar to sweep continuously instead of locking:

1. run() loop set radar to Inf every tick, overwriting any lock
   → replaced with enemy_tracker.getRadarTurnRate()

2. onScannedBot used radarBearingTo() (math convention, east=0 CCW)
   → removed; run loop now handles radar via enemy_tracker

3. enemy_tracker.getRadarTurnRate() had arctan2(dx,dy) instead of
   arctan2(dy,dx) — introduced by fd22535; bearing was off by ~90°

Also relaxed stale-lock threshold from 2 to 8 ticks to survive
brief scan gaps without falling back to full sweep.

Added tools/battle_runner for automated 1v1 testing.

Result: 1303/1308 ticks with successful scan (was ~1 in 4).

PPO_Bot/config.nims

@@ -1,6 +1,6 @@
 # Static-link OpenBLAS for portable deployment
 # ponytail: adjust path per machine, or use pkg-config
-switch("passL", "-lopenblas")
+switch("passL", "-L/nix/store/v07svn2y92bvzjl51aj7c9ca1cwg7rw7-openblas-0.3.32/lib -lopenblas")
 switch("threads", "on")
 # begin Nimble config (version 2)
 when withDir(thisDir(), system.fileExists("nimble.paths")):