Bobby the Friend

# Changelog
## 2.0.0 — The gear actually works
The headline is short and slightly embarrassing: in 1.0.0 **none of Bobby's gear
slots worked, and his attacks never damaged a single zombie.** Both are fixed, and
with the slots alive the mod is a different thing to play.
### Fixed
- **His attacks did no damage to zombies. Ever.** `EntityAlive.DamageEntity`
discards a hit outright when attacker and target are both flagged as zombies —
the rule that stops a horde tearing itself apart — and Bobby is an `EntityZombie`.
Every swing, shot and punch he ever aimed at a walker was thrown away before a
damage number was even worked out. He now carries a different entity flag.
This hid well: animals are flagged differently, so he could kill a wolf and never
a zombie, which read as "the weapon does nothing" rather than a flat rule. The
check is symmetric, so it also meant zombies could not hurt *him* — see *Changed*.
- **The weapon and tool slots refused every item in the game.** They tested whether
an item's action was an `ItemActionAttack`. Every real melee weapon and tool uses
`ItemActionDynamic`, which is not a subclass of it but a sibling. Nothing was ever
accepted.
- **Items dropped on a slot that did not accept them were destroyed.** By the time
the mod is asked about a drop, the dragged item is already out of the cursor and
in the cell, so a slot that "refused" by redrawing itself deleted the item.
Refused items are now handed back, or dropped at Bobby's feet if your bag is full.
- **The meat upgrades gave nothing.** Their bonuses were passive effects on a buff,
which were never felt in game — not even the +400% one. All bonuses now live in
code, in one place, and are printed to the log and shown in his stat panel.
- **Every icon in his radial menu was blank.** The radial builds the sprite name
itself (`ui_game_symbol_` + what you gave it), so the mod's custom names could
never resolve. The menu now shows its icons.
### Added
- **Firearms.** Any gun, bow or crossbow in t…