fix(botapi): static SVG + intent buffers to kill cross-thread heap realloc

Round N+1's fresh bot thread realloc'd module-level strings/seqs (SVG buffer,
intent stdout/stderr, team messages) left behind by dead round N's thread —
same rawDealloc SIGSEGV class as the event queue, seen at graphics.nim:274
(drawText->prepareAdd, core 2490478 @ 03:13:40, battle round 257).

- graphics.nim: gSvgBuffer -> array[16384, char] + gSvgLen, appendSvg
- bot.nim: intent stdout/stderr -> static char arrays; team messages ->
  array[16, TeamMessage] + len; buildIntentJson/printToStdOut/Err/
  broadcastTeamMessage bounded appends
- botThreadEntry: reset graphics+intent buffers on the owning thread

Also fixes stale mapActions call sites in tests/ (missing enemyX/enemyY).

PPO_Bot/tests/test_network.nim

@@ -40,7 +40,7 @@ when isMainModule:
   let raw = randomNormalTensor[float32](ACTION_DIM)
   let speed = 4.0'f32
   # arena 800×600, bot at centre, heading north, gun north
-  let botActs = mapActions(raw, 0.0'f32, 800.0, 600.0, 400.0, 300.0, 0.0, speed.float, 0.0)  # gunHeat=0 → fire allowed
+  let botActs = mapActions(raw, 0.0'f32, 800.0, 600.0, 400.0, 300.0, 0.0, speed.float, 0.0, 400.0, 300.0)  # gunHeat=0 → fire allowed
 
   assert botActs.targetSpeed >= -8.0'f32 and botActs.targetSpeed <= 8.0'f32,
     &"targetSpeed out of range: {botActs.targetSpeed}"
@@ -52,7 +52,7 @@ when isMainModule:
     &"firePower out of range: {botActs.firePower}"
 
   # shouldFire=false when gunHeat > 0
-  let noFire = mapActions(raw, 1.0'f32, 800.0, 600.0, 400.0, 300.0, 0.0, speed.float, 0.0)
+  let noFire = mapActions(raw, 1.0'f32, 800.0, 600.0, 400.0, 300.0, 0.0, speed.float, 0.0, 400.0, 300.0)
   assert not noFire.shouldFire, "shouldFire should be false when gunHeat > 0"
 
   echo "All tests passed"