j160 (default-off): the energy-reserve FIRING FLOOR + ENEMY-EXHAUSTION ram trigger

TR_RAM_FLOOR_ENERGY (0.0 = off): at/below this self energy we start no NEW
shot, holding back the reserve for a final ram exchange. Justified by the only
energy gain in the game being +3*power per bullet hit LANDED, so not firing
denies the enemy its only refill. Blocks only NEW shots (gunHeat already gates
committed ones) and is bypassed while ramming.

TR_RAM_ENEMY_ENERGY (0.0 = off): last-scanned enemy energy <= this -> ram
mode. Enemy energy IS observable (ScannedBotEvent.energy, schemas.nim:306),
1-8 ticks stale. This is the shipped finisher with its energy tolerance
promoted to a knob, keeping the self>enemy surplus guard because RAM_DAMAGE
0.6 applies to BOTH bots on every contact tick.

Open-loop measurement (measure_ramfloor_energy, 8149 recordings / 29871
rounds / 33.8M ticks): 'both low' is COMMON (10.4% of ticks below 20, 15.1%
below 25) but neither side goes low first (enemy 52.7% / us 47.3%), and the
owner's literal trigger - enemy so low it cannot fire (energy <= 1.95) - is
only 2.5% of ticks, 1.1% while we are healthy.

Guards 136 -> 147 in test_tfil_commit_env.nim, all green. A/B PRE-REGISTERED
in docs/ram_floor_exhaustion_ab.md and NOT RUN.

ModularBot_garage/.env.example

@@ -98,6 +98,8 @@ TR_RAM_PLAN=off            # the change-of-plan trigger (enemy outguns us while
 TR_RAM_PLAN_DIST=250.0     # px; max range at which the plan trigger may fire
 TR_RAM_PLAN_MARGIN=20.0    # energy advantage the plan trigger needs
 TR_RAM_PLAN_HITRATE=0.05   # pooled virtual hit rate below which the gun duel counts as failing
+TR_RAM_FLOOR_ENERGY=0.0    # j160 firing floor: at/below this self energy stop firing (0 = off)
+TR_RAM_ENEMY_ENERGY=0.0    # j160 exhaustion: last-scanned enemy energy <= this -> ram (0 = off)
 
 # ── movement internals: tfil (the floor-is-lava field) ──────────────────────
 TR_TFIL_RANGE_LO=100.0   # px; lower edge of the range band the ring mover prefers