Limb system changes neccesary to move mutations over

[Venera3]

Migrating our mutated kinda-sorta limb traits over to the new limb system will need a lot of functionality currently missing, and a good number of variables that live in trait definitions would make more sense as limb properties. This issue is meant as a centralized wishlist/discussion of the necessary features, to keep things tidier than pestering KorGgent on Discord.

Definitely necessary for migrating mutated limbs

• Copy-from support for limbs
• Body parts' flags counting as character flags -- Move bodypart flags to character flags #52723
• Glare factor on sensor limbs, glare application checking for sensors with vision score for it For the moment a character flag works well enough.
• Mutation armor moved to the limb definition - Natural Resistances #53462
• Monster special attacks limb targeting based on limb subtype / limb volume (see below) - Modify monster melee targeting #53089
• Replacement limbs inheriting the original limb's HP (scaled to the max HP of the resulting limb)
• Removing the main part of a minor part crashes the game on entering the @ menu
• Ranged attacks targeting respecting new bodyparts (currently uses hardcoded ids)
• Limb type/bodytype-based armor coverage (currently uses explicit bodypart IDs) Proposed armor changes to accomodate custom bodyparts #54939
• Limb connectedness being flexible enough to handle upstream limbs being replaced before invalidating the whole anatomy Bodypart connectedness is too inflexible (Limb Project blocker) #53453

Not strictly speaking necessary, but logical enhancements of the system

• Mutation attacks could probably move over to the limbs themselves, possibly with decreasing use chance on damage/derived from their scores Allow limbs to define MA techniques and unarmed damage, expand MA tech functionality #53939
• An absolute limb volume instead of the melee weights (those can be derived from volume or overwritten by the limb def explicitly) to facilitate dynamic special attack/spell targeting and maybe feed into height/weight calculations down the line Include extra bodyparts in dodge calculations #54819
• Moving visibility/ugliness in the limb definitions, influenced by the limb's armor coverage Allow ugliness to be defined per bodypart, allow covering up those ugly bits #55295
• Defining mutation costs for sprouting/resorbing limbs (calories, vitamins, pain etc) - doable as it stands with EOCs
• Limb replacement/removal defined by limb subtypes instead of explicit ID
• Replacing/removing an arbitrary number of limbs of a given subtype to facilitate one limb turning into another
• Utilizing anatomy definitions (anatomy_json) to define the base bodytype mutations strive towards and allowing mutation thresholds to modify the anatomy category - for a "normal" human limb mutations should be more likely to be replacements, for a posttresh Spider as long as they don't have their 8 limbs they should be more likely to gain more limbs.

Additional context

@KorGgenT @Ramza13 (touches on your character flag/bionic unhardcoding work, and EOCs could possibly be utilized in some form for some of this)

[I-am-Erk]

We also need to make limbs separate in sprites if we're doing this, so a sprite wouldn't just be a full skin but an arm_left, arm_right, leg_left, leg_right, torso, head, etc... Otherwise it will be very difficult to render mutations

[MylieDaniels]

Armor coverage struggles with new limbs, which cannot be covered at all presently. [EDIT: They may be covered by new clothing referencing their id, but this is not a good solution in my opinion.]
In addition, the Limbs and Armor widgets need some work, as presently:
For Limbs and other widgets that contain limb health, all limbs with a defined "hp_bar_ui_text" will attempt to display, but there is only room for 6. In compact and labels narrow, this pushes other parts of the widget around, while in classic and labels, this forces only the top 6 to display.
For Armor, only the default 5 groups can be displayed.