GameState._advance_distorder_drain() runs in GameState._process() -
not the distorder component's tick() - alongside extractor mining and
production, so it (and the fleet's travel) keeps working across the
space<->surface scene swap. Drain scales with how far above 1.0 the
multiplier is: (fleet_speed_multiplier - 1.0) / (MAX - 1.0) *
ENERGY_DRAIN_PER_SECOND (2.0 at full boost), accumulated fractionally
the same way extractor mining_progress is so small multipliers still
drain a nonzero amount instead of rounding to zero every frame.
Running the fleet hold's energy to exactly zero force-resets
fleet_speed_multiplier to 1.0 and raises a one-shot
boost_depleted_notice flag, since GameState can't reach into whichever
scene's SpeedFader may or may not currently exist. SpeedFader.gd
consumes the flag on its next _process(), snaps its knob down (it was
already reading the multiplier live, so this falls out for free) and
shows "Out of energy!" - also clearing active_touch_index so a
still-held drag can't immediately re-boost from the position the
finger never moved away from.
test_space_time_distorder.gd (#59) updated to stock fleet energy
first, for the same reason #60/#61 needed it: boosting is no longer
free, and that test's own multi-second boosted phases would otherwise
get cut short mid-measurement by running out.
