Garrison laser vessels and gas bombers, on a shared ability seam

#105 shipped with interceptors as the only garrisonable vessel, and the
reason was a design fault rather than a decision: firing the laser and the
gas bomb lived in the player's fleet controllers, so a stationed laser would
have held its position and never shot.

The shot is now a thing in the world rather than something a controller
draws. LaserBeamEffect and GasBombEffect are self-contained, self-animating
and self-freeing, added to the tree root - the same shape EnemyBigLaserBeam
and ArtilleryShell already had on the enemy side - and they outlive the
vessel that fired them.

Above them sits one seam, on VesselCooldownFillComponent: ability_range(),
ability_ammo_resource(), ability_ammo_cost() and fire_ability(). A beam and a
bomb are now the same shape of thing to whoever pulls the trigger, so the
garrison AI never names an ability - the test asserts that literally, by
reading the AI's own source. A third armed vessel needs to implement the
seam and nothing else.

Ammunition is the CALLER's business, deliberately: the fleet spends from its
hold, a garrison from its outpost's store, and neither concern belongs in
the component. A garrison with an empty magazine holds fire rather than
falling back on the fleet's hold.

Outpost storage: 50 gas per stationed bomber and 50 energy per stationed
laser, off the VESSEL definitions, so an outpost never learns which vessel
needs what. It is a capacity, not a stock - hub transporters fill it exactly
as they fill a gas burner's buffer, because building_logistics_deficit now
takes the larger of the definition's static buffer and the garrison's
magazine. Every other resource is capped at zero: an outpost is not a depot,
and ore parked at one has nothing to do there and no transporter coming for
it.

Also restores two properties the Godot editor dropped from
GasBurnerBuildingDefinition.tres when it re-saved the file:
collected_outputs and capabilities. Without the first, nothing ever collects
the burner's energy - test_gas_burner caught it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

vessels/VesselGarrisonComponent.gd

@@ -86,17 +86,44 @@ func _engage(ship: Node2D, target: Node2D, delta: float) -> void:
 	# snap the vessel back to whatever bearing it left on.
 	_angle += orbit_speed * delta
 
-	var weapon: Node = ship.get_component("weapon") if ship.has_method("get_component") else null
-	if weapon == null:
-		return
-	if distance <= weapon.fire_range:
-		weapon.set_fire_direction(to_target)
-	else:
-		weapon.set_fire_direction(Vector2.ZERO)
+	_shoot(ship, target, distance, to_target)
+
+
+# Two kinds of armament, one rule: point the gun, or fire the ability. Which
+# one this vessel has is a question about its components, not about its type,
+# so a third armed vessel needs nothing here.
+func _shoot(ship: Node2D, target: Node2D, distance: float, to_target: Vector2) -> void:
+	var weapon: Node = _component(ship, "weapon")
+	if weapon != null:
+		# The gun is a held trigger: it is aimed every tick and stops the
+		# moment the direction is cleared.
+		weapon.set_fire_direction(to_target if distance <= weapon.fire_range else Vector2.ZERO)
+	for component in ship.get_children():
+		if not component.has_method("fire_ability") or not component.has_ability():
+			continue
+		if not component.is_ready() or distance > component.ability_range():
+			continue
+		# The magazine is the OUTPOST's, not the fleet's hold. A garrison
+		# spends what was flown out to it, which is the whole point of the
+		# outpost holding a store at all - and if the store is empty the
+		# vessel holds its fire rather than firing free shots.
+		var resource_type: String = component.ability_ammo_resource()
+		var cost: int = component.ability_ammo_cost()
+		if not GameState.spend_garrison_ammo(outpost_id, resource_type, cost):
+			continue
+		if not component.fire_ability(get_tree().root, ship.global_position,
+				target.global_position):
+			# It refused after being paid - put the ammunition back rather
+			# than burning it on a shot that never happened.
+			GameState.building_inventory(outpost_id).deposit(resource_type, cost)
+
+
+func _component(ship: Node2D, capability: String) -> Node:
+	return ship.get_component(capability) if ship.has_method("get_component") else null
 
 
 func _hold_fire(ship: Node2D) -> void:
-	var weapon: Node = ship.get_component("weapon") if ship.has_method("get_component") else null
+	var weapon: Node = _component(ship, "weapon")
 	if weapon != null:
 		weapon.set_fire_direction(Vector2.ZERO)