Fixes Clarke ore box breaking upon collecting boulders (#85924)

## About The Pull Request

Ever since Clarkes could pick up boulders they've been broken if you
ever collected one. The UI would break and all your precious minerals
would be trapped inside the Clarke, only being obtainable if you broke
the Clarke itself.

This also updates the Clarke Storage to differentiate by ore name rather
than icon, as otherwise the lower quality boulders would be mixed with
normal boulders with no way to differentiate them in the UI.


## Why It's Good For The Game

Fixes https://github.com/tgstation/tgstation/issues/84364
Before:
<details>
  <summary>Before</summary> 


https://github.com/user-attachments/assets/f90daf35-733a-42bd-8af5-7e6712f09fba

</details>
<details>
<summary>After</summary> 


https://github.com/user-attachments/assets/4510803c-6dee-403e-a051-966a8a66c17c



</details>


## Changelog

🆑 TwistedSilicon
fix: Clarkes will no longer become unable to dump ores upon picking a
boulder up. Mine away.
/🆑

code/modules/mining/boulder_processing/boulder.dm

@@ -22,6 +22,8 @@
 	var/boulder_size = BOULDER_SIZE_SMALL
 	/// Used in inheriting the icon_state from our parent vent in update_icon.
 	var/boulder_string = "boulder"
+	// There is one boulder per boulder (this is required for the Clarke UI as it treats ores and boulders in the same fashion and needs an amount for both)
+	var/amount = 1
 
 /obj/item/boulder/Initialize(mapload)
 	. = ..()