Implement production vertical slice foundation

game/domain/dive/dive_tick.gd

@@ -0,0 +1,28 @@
+class_name DiveTick
+extends RefCounted
+
+var session_id: StringName
+var sequence: int
+var elapsed_seconds: float
+
+
+func _init(
+	p_session_id: StringName,
+	p_sequence: int,
+	p_elapsed_seconds: float
+) -> void:
+	session_id = p_session_id
+	sequence = p_sequence
+	elapsed_seconds = p_elapsed_seconds
+
+
+func validation_error() -> String:
+	if session_id.is_empty():
+		return "tick session_id is empty"
+	if sequence < 0:
+		return "tick sequence is negative"
+	if not is_finite(elapsed_seconds) or elapsed_seconds <= 0.0:
+		return "tick duration must be finite and positive"
+	if elapsed_seconds > 0.1:
+		return "tick duration exceeds 0.1 seconds"
+	return ""