Fuelweaver changes

[Bumber64]

AFW has some irritating mechanics for a solo player. There are also some other wanted adjustments.

Solo considerations:

• Allow pickaxe and hammer to work on bone cage. This takes a few hits, so AFW still gets to smack you, but you can probably prevent him from healing too much when it happens during woven shadows.
• Give an early warning he's about to use the cage. Enough to swap items comfortably. Slight increase on cage ability cooldown?
• Make AFW consume woven shadows more slowly. Players no longer need to walk him away from the center of the arena to prevent being overwhelmed, but doing so still helps in preventing his heals.

Remove cheese:

• Bone cage fully forms on arena edges, properly trapping the player.
• AFW attacks any constructed pillars, etc., blocking his path to the targeted player or gateway.
• Make AFW impossible to hit from outside the arena.

QoL:

• Prevent accidental targeting of AFW during shield. Require force attack if there's any good reason to allow it.
• Make hostile shadows deaggro better when sane. Applies outside of AFW fight.

Buffs:

• Make fossil spikes harder to dodge.
• Possibly add a new attack if the fight is left too easy after changes. Maybe a small lingering AoE, or a variant on fossil spikes?

I've heard some players complain that the sanity threshold for mind control is too high? But you can simply avoid it by just staying as sane as possible while he's not shielded.