Fix headless class_name dependencies

- Replaced TeamData.Team type hints with int in all scripts
- Added explicit preloads for headless mode class resolution
- Created stub LagCompensation and DamageProcessor scripts
- Fixed PluginManager, SpawnManager, EconomyManager, BuyZone,
  RoundManager, BuyMenuHandler, BombObjective class_name references
- Updated server config to match ServerConfig.gd format

Gray screen root cause: server scripts failed to parse in headless
mode due to Godot 4 class_name loading order (Resource after Node),
leaving server_main.gd non-functional — accepted connections but
never spawned players.

server/scripts/combat/damage_processor.gd

@@ -0,0 +1,37 @@
+## DamageProcessor — applies hit results, tracks health and kills.
+## Minimal stub for server startup compatibility.
+extends Node
+## class_name DamageProcessor — commented out for headless compatibility
+
+signal player_damaged(victim_entity_id, shooter_entity_id, damage, killed)
+signal player_killed(victim_entity_id, killer_entity_id)
+
+var _health: Dictionary = {}  # entity_id → current_health
+const MAX_HEALTH = 100
+
+func register_entity(entity_id: int) -> void:
+	_health[entity_id] = MAX_HEALTH
+
+func unregister_entity(entity_id: int) -> void:
+	_health.erase(entity_id)
+
+func apply_damage(victim_entity_id: int, shooter_entity_id: int, damage: float, weapon_id: String = "") -> Dictionary:
+	var current = _health.get(victim_entity_id, MAX_HEALTH)
+	current -= damage
+	_health[victim_entity_id] = current
+	var killed = current <= 0.0
+	if killed:
+		_health[victim_entity_id] = MAX_HEALTH  # reset for respawn
+		player_killed.emit(victim_entity_id, shooter_entity_id)
+	player_damaged.emit(victim_entity_id, shooter_entity_id, damage, killed)
+	return {
+		damage_dealt = damage,
+		killed = killed,
+		remaining_health = max(current, 0.0),
+	}
+
+func get_health(entity_id: int) -> float:
+	return _health.get(entity_id, MAX_HEALTH)
+
+func reset_all() -> void:
+	_health.clear()