feat: add melee detection to the damage dataset

[ghaif]

Problem

The damage dataset could not tell whether a hit was a melee attack. load_damage decodes the full CCitadelUserMessage_Damage protobuf but surfaced only 10 of its fields, dropping ability_id, type, and citadel_type, which are the fields that identify a hit.

Change

Surface those fields on the damage frame and add an is_melee convenience flag:

• ability_id: the ability that dealt the hit (0 if none; resolve with ability_names())
• damage_type: the raw type bitfield
• citadel_type: Deadlock's damage-type category (3 is melee damage)
• is_melee: a light/heavy melee attack

is_melee is citadel_type == 3 AND a hit from a melee ability (its name contains melee). citadel_type == 3 on its own is too broad: it also tags melee-typed abilities (uppercut, hook, crushing fists) and ownerless auto-melees (ability_id == 0, e.g. a trooper's own swing). Restricting to a melee ability keeps a hero's light and heavy melee against any target (heroes, troopers, denizens) and drops the rest. citadel_type stays exposed for anyone who wants the broad damage type.

The melee-id set is derived once from all_abilities(), so it is cheap and stays correct as heroes are added.

Tests

crates/boon-python/tests/test_demo.py: extend the damage schema test and add TestDamageMelee (the new fields resolve and are typed; is_melee equals citadel_type == 3 combined with a melee-ability hit; a match lands at least one melee).