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/VesselDefinition.gd

@@ -24,6 +24,13 @@ extends Resource
 	Vector2(0, -22), Vector2(-14, 16), Vector2(14, 16),
 ])
 @export var fleet_eligible: bool = false
+# What one of these keeps beside it when stationed at an outpost, and which
+# resource that is. Data here rather than a table in the outpost, so a new
+# armed vessel brings its own magazine with it and the outpost never has to
+# learn about it. 0 means it needs no ammunition to fight - the interceptor's
+# gun is the case that does.
+@export var garrison_ammo_resource: String = ""
+@export var garrison_ammo_capacity: int = 0
 @export var capabilities: PackedStringArray = []
 @export var component_scenes: Array[PackedScene] = []
 @export var base_stats: Dictionary = {}