Add the Evil Tree Distraction & Diversion

[HarleyGilpin]

Builds on the existing evil-tree work in progress and finishes it so the event can be played end to end: a seedling sprouts somewhere in the world, grows into a tree, gets chopped and burned down, and pays out rewards.

Reference: 2011 wiki for the numbers and the flow.

Event lifecycle

Two world timers drive the event — evil_tree_spawn schedules the next tree, evil_tree ticks the live one. Timers rather than World.queue because clearing a queue invokes its pending block, which would respawn a tree during teardown.

A tree sprouts two minutes after startup and two hours after the last one died, both configurable, and its location is announced when world.messages is on.

Growth

Saplings advance a stage every seed_health growth points, gained either from the growth timer or from nurturing, which pays the tier's farming experience spread across the stage. Roots briefly shoot out of the ground near a sprouting sapling, once per player per tree. The final stage displaces anyone standing where the 3x3 tree appears, sets the tree's health and bursts four roots out of the ground.

Chopping and burning

• Chopping the trunk uses the woodcutting success rates of the matching log and takes a point of health per successful chop; the tree swaps to its damaged and dying models at two thirds and one third health.
• Chopping a root yields evil tree kindling and dies after three to seven successful chops. A replacement root bursts out every minute, shoving and stunning anyone stood on top of it.
• Lighting kindling against the trunk places a fire in one of the twelve spots around the tree; every lit fire burns a point of health per tick cycle.
• Lightning strikes at ten, twenty and thirty minutes, capping the tree at half then a quarter of its health before felling it outright.

Rewards

Kindling is the currency. It's handed in to the leprechaun or taken from the reward stump (varbit 1542 picks the reward or blank stump per player), capped at two hundred a day, paying coins, noted logs and "evil tree magic" scaled by the amount handed in. Evil tree magic halves the chance of felling a tree, escorts logs to the bank once the inventory is full and doubles the bird's nest rate.

Players can help with two trees a day; inspecting a tree doesn't count towards that.

Fixes to the work in progress

• The growth timer registered player handlers (timerStart/timerTick) against an npc timer, so the body never ran and a zero interval task span every tick.
• A string concatenation in the stage when ("evil_tree_young" + "evil_tree_young_large") meant neither young stage matched.
• The burning code checked and removed kindling, the Lunar Diplomacy item, rather than evil_tree_kindling.
• chop and light were never wired to an option, so a single click advanced a whole stage with no level check, animation or experience.
• wander_radius isn't a valid npc parameter and threw on startup; wander ranges live in the npc_ranges table.
• tree_xp held the wiki's root experience values; corrected both columns against the wiki, along with elder's burn experience and woodcutting level.
• The spirit tree referenced an object id (strange_sapling) that doesn't exist, so its sapling branch was unreachable, and its countdown was a placeholder. Both now work off the live event state.

Testing

EvilTreeTest covers growth by nurture and by timer, the growth spurt, chopping the trunk and the roots, root death, burning kindling, fire damage, the lightning strikes, death and respawn scheduling, the reward stump, the tool loan, and both daily limits. Full suite passes.