fix(PPO_Bot): SIGSEGV crash fixes + static buffers for thread safety

- bullets: seq[InFlightBullet] → array[4, InFlightBullet] + bulletCount
  (eliminates cross-thread heap realloc under ORC)
- hasFired: edge-triggered (cleared after state build, not level-triggered)
- round_counter parseInt: wrapped for empty/torn file → 0
- Static SVG + intent buffers to kill cross-thread heap realloc
- Tick-local alive/bulletData also fixed arrays

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

PPO_Bot/weights.nim

@@ -33,26 +33,30 @@ proc saveWeights*(ac: ActorCritic, dir: string) =
   ac.logStd.write_npy(dir / "log_std.npy")
 
 proc loadWeights*(ac: var ActorCritic, dir: string) =
-  ## Load all weight tensors from dir/. Asserts shapes match.
-  template loadAndCheck(dest: untyped, path: string) =
+  ## Load all weight tensors from dir/.
+  ## If a tensor's shape doesn't match (e.g. STATE_DIM changed), keep the
+  ## freshly-initialised value and print a warning — other tensors still load.
+  template loadOrSkip(dest: untyped, path: string) =
     let loaded = read_npy[float32](path)
-    doAssert loaded.shape == dest.shape,
-      "Shape mismatch loading " & path & ": got " & $loaded.shape & " want " & $dest.shape
-    dest = loaded
+    if loaded.shape == dest.shape:
+      dest = loaded
+    else:
+      echo "weights: shape mismatch for " & path &
+           " (got " & $loaded.shape & " want " & $dest.shape & ") — keeping fresh init"
 
-  loadAndCheck(ac.actor.w1,  dir / "actor_w1.npy")
-  loadAndCheck(ac.actor.b1,  dir / "actor_b1.npy")
-  loadAndCheck(ac.actor.w2,  dir / "actor_w2.npy")
-  loadAndCheck(ac.actor.b2,  dir / "actor_b2.npy")
-  loadAndCheck(ac.actor.w3,  dir / "actor_w3.npy")
-  loadAndCheck(ac.actor.b3,  dir / "actor_b3.npy")
-  loadAndCheck(ac.critic.w1, dir / "critic_w1.npy")
-  loadAndCheck(ac.critic.b1, dir / "critic_b1.npy")
-  loadAndCheck(ac.critic.w2, dir / "critic_w2.npy")
-  loadAndCheck(ac.critic.b2, dir / "critic_b2.npy")
-  loadAndCheck(ac.critic.w3, dir / "critic_w3.npy")
-  loadAndCheck(ac.critic.b3, dir / "critic_b3.npy")
-  loadAndCheck(ac.logStd,    dir / "log_std.npy")
+  loadOrSkip(ac.actor.w1,  dir / "actor_w1.npy")
+  loadOrSkip(ac.actor.b1,  dir / "actor_b1.npy")
+  loadOrSkip(ac.actor.w2,  dir / "actor_w2.npy")
+  loadOrSkip(ac.actor.b2,  dir / "actor_b2.npy")
+  loadOrSkip(ac.actor.w3,  dir / "actor_w3.npy")
+  loadOrSkip(ac.actor.b3,  dir / "actor_b3.npy")
+  loadOrSkip(ac.critic.w1, dir / "critic_w1.npy")
+  loadOrSkip(ac.critic.b1, dir / "critic_b1.npy")
+  loadOrSkip(ac.critic.w2, dir / "critic_w2.npy")
+  loadOrSkip(ac.critic.b2, dir / "critic_b2.npy")
+  loadOrSkip(ac.critic.w3, dir / "critic_w3.npy")
+  loadOrSkip(ac.critic.b3, dir / "critic_b3.npy")
+  loadOrSkip(ac.logStd,    dir / "log_std.npy")
 
 proc saveWeightsAtomic*(ac: ActorCritic, targetDir: string) =
   ## Write to a temp dir, then rename atomically over targetDir.
@@ -104,8 +108,14 @@ proc saveAdamStates*(adam: ACAdamStates, dir: string) =
 
 proc loadAdamStates*(adam: var ACAdamStates, dir: string) =
   ## Load Adam m/v tensors and t counters from dir/. Called only when files exist.
+  ## Shape mismatch (e.g. STATE_DIM changed) → keep zero-initialised state (safe fresh start).
   template lm(dest: untyped, path: string) =
-    dest = read_npy[float32](path)
+    let loaded = read_npy[float32](path)
+    if loaded.shape == dest.shape:
+      dest = loaded
+    else:
+      echo "weights: Adam shape mismatch for " & path &
+           " (got " & $loaded.shape & " want " & $dest.shape & ") — resetting Adam state"
   lm(adam.aw1.m,    dir / "adam_aw1_m.npy");    lm(adam.aw1.v,    dir / "adam_aw1_v.npy")
   lm(adam.ab1.m,    dir / "adam_ab1_m.npy");    lm(adam.ab1.v,    dir / "adam_ab1_v.npy")
   lm(adam.aw2.m,    dir / "adam_aw2_m.npy");    lm(adam.aw2.v,    dir / "adam_aw2_v.npy")
@@ -185,7 +195,11 @@ proc loadBestAvailable*(ac: var ActorCritic, adam: var ACAdamStates,
         if adamStateFilesExist(candidate):
           adam.loadAdamStates(candidate)
         let rcPath = weightsRoot / "round_counter.txt"
-        let roundNum = if fileExists(rcPath): parseInt(readFile(rcPath).strip()) else: 0
+        # Torn/empty file (e.g. after a crash) must not abort startup → treat as 0
+        let roundNum = if fileExists(rcPath):
+          try: parseInt(readFile(rcPath).strip())
+          except ValueError: 0
+        else: 0
         return (loaded: true, roundNum: roundNum)
   result = (loaded: false, roundNum: 0)