Reworks pAIs (#68241)

A pretty heavy refactor for pAIs that just spilled into a rework.

Attempts to fully document and organize backend code.
Fixes a large number of bugs left untouched for a decade.
Breaks down the frontend into subcomponents.
Rebalances their software modules.
(should) fix pAI faces get removed if you activate them during alert #68242

code/modules/pai/camera.dm

@@ -0,0 +1,58 @@
+/mob/living/silicon/pai/ClickOn(atom/target, params)
+	..()
+	if(!camera?.in_camera_mode)
+		return FALSE
+	//pAI picture taking
+	camera.toggle_camera_mode(sound = FALSE)
+	camera.captureimage(target, usr, camera.picture_size_x - 1, camera.picture_size_y - 1)
+	return TRUE
+
+/obj/item/camera/siliconcam/pai_camera
+	name = "pAI photo camera"
+	light_color = COLOR_PAI_GREEN
+
+/obj/item/camera/siliconcam/pai_camera/after_picture(mob/user, datum/picture/picture)
+	var/number = length(stored)
+	picture.picture_name = "Image [number] (taken by [loc.name])"
+	stored[picture] = TRUE
+	playsound(loc, pick('sound/items/polaroid1.ogg', 'sound/items/polaroid2.ogg'), 75, TRUE, -3)
+	balloon_alert(user, "image recorded")
+
+/**
+ * Handles selecting and printing stored images.
+ *
+ * @param {mob} user - The pAI.
+ *
+ * @returns {boolean} - TRUE if the pAI prints an image,
+ * 	FALSE otherwise.
+*/
+/obj/item/camera/siliconcam/pai_camera/proc/pai_print(mob/user)
+	var/mob/living/silicon/pai/pai = loc
+	var/datum/picture/selection = selectpicture(user)
+	if(!istype(selection))
+		balloon_alert(user, "invalid image")
+		return FALSE
+	printpicture(user, selection)
+	user.visible_message(span_notice("A picture appears on top of the chassis of [pai.name]!"), span_notice("You print a photograph."))
+	return TRUE
+
+/**
+ * All inclusive camera proc. Zooms, snaps, prints.
+ *
+ * @param {mob} user - The pAI requesting the camera.
+ *
+ * @param {string} mode - The camera option to toggle.
+ *
+ * @returns {boolean} - TRUE if the camera worked.
+ */
+/mob/living/silicon/pai/proc/use_camera(mob/user, mode)
+	if(!camera || isnull(mode))
+		return FALSE
+	switch(mode)
+		if(PAI_PHOTO_MODE_CAMERA)
+			camera.toggle_camera_mode(user)
+		if(PAI_PHOTO_MODE_PRINTER)
+			camera.pai_print(user)
+		if(PAI_PHOTO_MODE_ZOOM)
+			camera.adjust_zoom(user)
+	return TRUE