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/VesselGasBomberComponent.gd

@@ -11,6 +11,28 @@ func _init() -> void:
 	cooldown_duration = 5.0
 
 
+const BOMB_EFFECT = preload("res://vfx/GasBombEffect.gd")
+const GAS_PER_SHOT: int = 5
+const MAX_RANGE: float = 950.0
+const BLAST_DAMAGE: int = 3
+const SHOT_COOLDOWN: float = 5.0
+
+
+func ability_range() -> float: return MAX_RANGE
+func ability_ammo_resource() -> String: return GameState.RESOURCE_GAS
+func ability_ammo_cost() -> int: return GAS_PER_SHOT
+func ability_cooldown() -> float: return SHOT_COOLDOWN
+
+
+func fire_ability(world: Node, origin: Vector2, at: Vector2) -> bool:
+	if not consume_shot(SHOT_COOLDOWN):
+		return false
+	# Unlike the beam, the bomb goes to the POINT it was aimed at, and it has
+	# to travel there - which is what makes it dodgeable.
+	BOMB_EFFECT.launch(world, origin, at, BLAST_DAMAGE)
+	return true
+
+
 func consume_shot(duration: float) -> bool:
 	return _begin_cooldown(duration)