laser requirements

docs/requirements.md

@@ -104,6 +104,8 @@ Output port indicators are not building tiles themselves. A building may have mo
 - REQ-SHP-MOVEMENT: Ships move in straight lines toward their current destination at the speed defined by their speed formula. Ship position refers to the ship's center for all range, sensor, and attack checks.
 - REQ-SHP-NO-COLLISION: Ships do not collide with each other or with defence stations; they may visually overlap.
 - REQ-SHP-SENSOR: A ship perceives only entities within its sensor range. Behavior is driven by what is in sensor range; entities outside sensor range are ignored.
+- REQ-SHP-FIRING: All weapons — on ships and on defence stations — are hitscan lasers. When a weapon is off cooldown and its target is within attack range, it fires: damage is applied instantly to the target with no projectile entity, no travel time, and no intervening collision. The weapon's cooldown then begins, derived from its fire rate formula.
+- REQ-SHP-FIRING-BEAM: Each fire event produces a visual laser beam drawn from the shooter's position to the target's position for 0.3 seconds. The beam is a pure rendering effect and has no simulation state (does not block movement, does not re-apply damage over its lifetime). Beams follow the shooter and target positions if either moves during the 0.3-second window.
 - REQ-SHP-ENEMY-AI: Enemy ships engage the closest valid target (player defence station, HQ, or player ship) within their sensor range. If no target is in sensor range, they move toward the asteroid (leftward in world coordinates).
 - REQ-SHP-COMBAT: **Combat ships** — move right through space and engage enemy ships. The player can configure the following per shipyard (applied to all ships produced by that shipyard):
   - Stance: aggressive (advance toward enemies) / defensive (hold position near asteroid).