[Jackriip]

Adds two plasma guns, two frontier laser guns, a refillable plasma flask, and plasma pirates.

Builds on feature/hitscan-lasers. That branch's commits are included here, so merge it first.

Guns

Gun	Fires	Where it comes from
Kestrel laser pistol	20-damage laser, 20 shots per cell	Outfitter, 900 cr
Hornet laser SMG	the stock hitscan laser, full auto	Black market, 3,500 cr
Cinder plasma pistol	32-burn plasma bolt	Outfitter at yellow rep, 2,000 cr
Furnace plasma rifle	45-burn plasma bolt, two-handed	Black market, 5,000 cr plus a voucher; red-zone loot
Old Furnace	Furnace variant	Rare drop from two red-zone pirate bosses only

How plasma works

• Bolts:
  • fly at 10 tiles/s
  • can't be reflected
  • are stopped by glass, which they damage
  • ignore canisters
• Burns, not fire: a hit never sets anyone alight. Bolts carry a high wound bonus (pistol 10, rifle 20), so hits cause real tg burn wounds: an unarmoured rifle hit gives at least a moderate burn about three times in four, and repeat hits on one limb reach severe and critical. A bolt still ignites real plasma or other fuel gas it passes through or hits.
• Limb loss: an arm or leg melts through tg's burn dismemberment (no blood spray, no flying limb) when it was already hurt (10+ damage) before the bolt and is left within 10 (pistol) or 20 (rifle) of its damage cap, or, for the rifle, when it already carries a critical burn. No bolt melts a healthy limb in one hit: it takes two rifle bolts on the same limb, two or three pistol bolts. Heads and chests never melt.
• Structure damage: bolts break structures and doors faster (pistol x1.5, rifle x2): a shuttle window takes 4 pistol or 2 rifle bolts, an airlock 8 or 4, a table 3 or 2. Grilles and blast doors still shrug them off. Mechs, turrets and other machines take normal damage, and walls take none.
• Ammo:
  • Guns run on a plasma flask: a plasma sheet adds 20 mol, ore 10, and a full flask holds 60.
  • The flask swaps like a magazine and works with no recharger.
  • The gun's chamber can't be charged by anything except a flask: rechargers, inducers, APCs, cell-charging slimes and plants are all refused.
• Furnace heat:
  • The rifle heats with each shot and cools from the air around it.
  • In vacuum it overheats: it vents plasma gas and takes damage.
  • Using it in hand vents on purpose.
  • The coil glows in steps as it heats.
• Turrets: plasma guns can't be put in turrets or emitters.
• Pirates: yellow- and red-zone pirate crews can carry the Cinder, and red-zone crews the Furnace. Two red-zone bosses carry Furnaces.

Effects

• Hits on people: a hit bursts into molten green slag. Ordinary hits alternate between a molten splatter and a flash with a spreading ring. A hit that kills or leaves a critical burn plays a burn-through instead, spraying out the far side of the body. Globs stick to the body, move and turn with it, and cool away in about 2.5 s. The flash starts as the bolt reaches the body, with a soft bloom and a small light on the victim.
• Melting limbs: a melted arm or leg heats up, sags and runs off in drips into a growing pool, then the stump bubbles and cools to a seared stump. The pool sets into slag that stays until it's cleaned (one per tile, 150 at most). The jumpsuit sleeve burns away at a melted arm. There's no blood splatter, though tg's blood loss still happens. Held items and shoes melt with the limb, then fall to the floor beside the feet. If the victim moves mid-melt, the limb goes with them and later drips land under them.
• Shields: a held shield blocks bolts at its normal chance and takes the damage; the block shows a plasma splash on the shield instead of the yellow block star.
• Bolts carry a moving green light.
• Impacts look different on walls, glass and armour.
• Hit spots on walls and floors glow green, cool to char and leave soot that stays until it's cleaned (soot is capped at 300, glows at 40 per z).
• A bolt that misses fizzles out at the end of its range.
• The Furnace vents with a puff.
• Each gun has its own fire sound, plus a distant version for listeners 18–40 tiles away. Plasma hits on people, burn-throughs and limb melts have their own sounds.

Media

Recorded in a real client at real speed, four facings.

Hits on people (splatter, flash and ring, burn-through):

Melting limbs (arm with gloves and a held crowbar, leg, lying, walking off mid-melt):

Shield block and wall/glass hits in the dark:

Assets

The gun sprites and the plasma, RCW and laser pistol sounds are from Mojave Sun (CC BY-NC-SA 3.0). The bolt, effect, burst and melt sprites, and the plasma hit, burn-through and melt sounds, are new. Each file's source and licence is listed in voidcrew/modules/plasma_weapons/icons/attributions.txt and sound/attributions.txt. There's a new player wiki page at wiki/content/plasma-and-laser-guns.md.

Also in this PR

__byond_var_id_padding.dm (the same file the hyperviolence branches carry) so the CI build stays clear of DM's broken variable id 65535.

Not playtested

It compiles cleanly under the normal and CI define sets, and the plasma unit tests pass. Every effect, burst and melt was recorded in a real client in all four facings. Still needs a human playtest:

• how dodging bolts feels
• how fast the Furnace heats up
• how often limbs melt, and how burn wounds feel to treat
• whether vented plasma catches fire in room air
• the near-miss hiss, distant fire, hit, burn-through and melt sounds
• the short client hitch the first time a client sees a melt