Changes:
- Code copied over to hud.dm and commented out, to prep for upstream pull.
- Commented-out, unused code removed.
- CHOMPEdits removed, pending upstream PR.
- Medigun no longer shows 2x the actual ammo loaded.
- Curabitur now fetches the amount of shots correctly, bar 1 extra for some reason.
- Curabitur ammo updates on automatic recharge ticks.
- A ton of projectile get_ammo_count optimization - mostly swaps the massive if/else for for loops. Fixes multiple guns not getting ammo properly, now casings won't register as ammo unless they have a shell in the casing.
- hud_state_empty defined as base on all bullets.
- Corrects energy weapons missing a hud_state_empty.
- Gives Ion weapons a hud_state_empty
All changes have been tested, and bar the Curabitur having an extra shot for ??? reason, which is a base bug I've yet to fix, this is entirely ready for testmerge.
The body zone selector now indicates which body part you are about to select when hovered over, and the hover inventory indicator basically shows where you are trying to put an item, and then shows an item ghost in red or green, giving visual feedback as to if that item will go in the slot or not.
Gifs of this in action:
 Body Selection parts.

Inventory Icon Overlays!
Credit goes to @ShadowLarkens for original port to Paradise and assistance with port to Virgo. Sending to Polaris ASAP.
- A note on `code/game/objects/items/weapons/storage/internal.dm`, VSCode automatically corrected the line endings, hence the massive filediff. The only practical changes are the addition of `disable_warning = 0`
EVA suit no longer stores toolboxes because those use a volume inventory.
CE's suit no longer holds pickaxes and ore satchels, but can now hold inflatables.
Adjusted get_breath_from_internal() proc to disable rig internals if the helmet is retracted and no suitable mask is in place.
Adjusted the internals button to ignore offline rigs.
Adds a HUD when controlling a simple animal. Allows intents, mostly harm and help if they don't have hands. Disarm and grab if they do. Gives them a generic hud, and adds a var to decide if they have hands or not. Adds a var printed to any client that joins into a mob to explain how to play them, or lore stuff, or whatever you feel like.
* Polaris initial plane upstream merge
* POLARIS: Fix RIG visors with new plane system, and material scanner VIS_FULLBRIGHT
* POLARIS: Fix GetFlatIcon so that cameras and id pictures don't show the HUD overlays.
* POLARIS: Adds a 'alter values' proc for plane master ease of tweaking
Setting stuff like colorblindness variety and things.
* Remove NIF reference, fix lighting layer define
* Handle effects above lighting plane
* Moved all layer defines to planes+layers.dm
* Fixed overlays that are supposed to be above lighting to use the PLANE_LIGHTING_ABOVE
* Merge: 3000% human/update_icons() speed improvement
* Merge: Avoid ghosts pointing at things
We define the inventory screen objects for hands to be special in that apply overlays to themselves for handcuffed. By putting that logic on the screen object itself, we allow it to be expanded to other cases besides handcuffs in the future without conflict.
More tweaks to IPC fixes.
Merge resolution/compile fixes.
Further work on properly integrating, updating and fixing prosthetic options.
Repathed internal organs to organ/internal.
More work on full synthetics, changelings, overheating.
Working on getting organs to qdel properly and spawn properly when robotized.
Finalized some overheating values, added remaining prosthetic icons.
Finalizing the testing version of the full prosthetic bodies branch.
Added suit cyclers to the autolathe and map.
Fixing runtime errors.
Fixing errors.
Changelog.
Replacing limb and organ strings with constants.
Prevented brainless species from becoming full cyborgs.
Fixed issues with brain/MMIs renaming themselves inappropriately.
Various fixes and oversights.