feat: implement player movement controller and initial weapon framework including double barrel shotgun and explosive projectiles

weapons/double_barrel_shotgun.gd

@@ -146,12 +146,11 @@ func _apply_impulse() -> void:
 	var push_dir = camera.global_transform.basis.z.normalized()
 	
 	# Apply impulse to player velocity
-	player.velocity += push_dir * impulse_strength
-	
-	# Small hack to ensure we aren't considered on floor if we shoot down
-	if push_dir.y > 0:
-		# Just slightly lift the player to break floor contact immediately
-		player.position.y += 0.05
+	var final_force = push_dir * impulse_strength
+	if multiplayer.has_multiplayer_peer() and multiplayer.multiplayer_peer is not OfflineMultiplayerPeer:
+		player.server_apply_impulse.rpc_id(1, final_force)
+	else:
+		player.apply_impulse(final_force)
 
 func _play_muzzle_flash() -> void:
 	if muzzle_flash:

weapons/explosive_projectile.gd

@@ -191,16 +191,19 @@ func _explode(pos: Vector3) -> void:
 		# Add a tiny bit of upward bias to knockback so it lifts them
 		dir = (dir + Vector3(0, 0.5, 0)).normalized()
 		
-		# Apply knockback if it has apply_impulse
-		if col.has_method("apply_impulse"):
-			col.apply_impulse(dir * final_knockback)
+		# Apply knockback if it has server_apply_impulse (for rocket jumping)
+		if col.has_method("server_apply_impulse") and col == owner_player:
+			if multiplayer.has_multiplayer_peer() and multiplayer.multiplayer_peer is not OfflineMultiplayerPeer:
+				col.server_apply_impulse.rpc_id(1, dir * final_knockback)
+			else:
+				col.apply_impulse(dir * final_knockback)
 			
-		# Apply damage
+		# Apply damage (and knockback for other players via take_damage)
 		if col.has_method("take_damage"):
 			if col == owner_player and not can_self_damage:
-				# Skip self damage, but we still applied the knockback!
+				# Skip self damage (we already applied knockback above)
 				pass
-			elif owner_player and owner_player.multiplayer.is_server():
+			elif owner_player:
 				col.take_damage(final_damage, target_pos, owner_player, dir * final_knockback)
 				
 	# Broadcast Visual Explosion Effect to other peers