Shots cost GAS_PER_SHOT (5) from GameState.fleet_inventory, not the
bank - the fleet has to be carrying its own ammunition. The button's
enabled rule now also requires affordability, and a press on a ready-
but-unaffordable bomber still consumes the touch to explain itself via
a new status label (GasBombStatus, IconButton's own "greyed but still
pressable" convention) rather than either silently doing nothing or
consuming the bomber's cooldown for a shot that never fires.
Also documents a real, reproducible GDScript trap hit while writing
tests/test_gas_bomber_ammo.gd: a bare `ClassName.SOME_CONST` reference
anywhere in a -s entry test script can corrupt method resolution for
the WHOLE script, making an unrelated, earlier `some_node._process()`
call fail with "Nonexistent function '_process' in base 'Nil'" despite
the node being valid and the method existing (confirmed via
has_method()). Root cause unconfirmed; fixed by mirroring the constant
's value into a local const instead of referencing the class directly,
in all three gas-bomber tests.
tests/test_gas_bomber.gd and test_gas_bomber_cooldowns.gd updated to
stock fleet gas first, since shots are no longer free.
Enemy.gd now resolves stats/hull/color from EnemyDefinition resources
and composes behaviour from capability components (EnemyPursuitComponent
holds today's chase-the-nearest-ship logic), the same shape Ship.gd
already uses for vessels. Fleet lookups go through a "player_fleet"
group instead of a hardcoded ../Fleet sibling path, so an enemy parented
anywhere (e.g. under a planet surface's SurfaceFeatures) still finds it.
Also closes a real gap: enemies previously had no way to damage the
fleet at range at all (Ship only reacted to physical contact,
Projectile.gd was player-only). Ship.take_damage() is now a proper
entry point - contact damage routes through it unchanged - and
EnemyProjectile lets an enemy component fire at player_ships. Both
ranged enemy archetypes in #45/#46 build on this.
Part of the #40 conquest-mechanic breakdown.
