Add CoPE material type (#11867)

# Description

This PR introduces a new material type called **CoPE** to the system.

**Changes:**
* **New Material:** Implemented `CoPE` as a selectable material type.
* **Configuration:** Added necessary material properties and parameters specific to CoPE.

**Breaking Changes:**
* None.

# Screenshots/Recordings/Graphs
<img width="1793" height="618" alt="image" src="https://github.com/user-attachments/assets/8577be4d-9f5f-4bda-b0de-c0842857625d" />
<img width="978" height="937" alt="image" src="https://github.com/user-attachments/assets/ec2ba1a3-41d5-4792-8fea-41c282136ff2" />

## Tests

I have verified the changes with the following tests:

* **UI Validation:** Verified that `CoPE` correctly appears in the software's material selection list.
* **Preset Management:**
  * Successfully **exported** a preset containing the CoPE material.
  * Successfully **imported** the CoPE preset back into the software.

src/libslic3r/MaterialType.cpp

@@ -24,6 +24,7 @@ const std::vector<MaterialTypeInfo>& MaterialType::all()
         {"ASA-GF",      240, 300, 50, 65,  1,   0.1 , 100},
         {"ASA-AERO",    240, 280, 50, 65,  1,   0.1 , 100},
         {"BVOH",        190, 240, 0,  70,  1,   0.02, 200},
+        {"CoPE",        190, 240, 0,  45,  1,   0.02, 200},
         {"EVA",         175, 220, 0,  50,  1,   0.02, 200},
         {"FLEX",        210, 230, 0,  50,  0.5, 0.02, 1000},
         {"HIPS",        220, 270, 50, 60,  1,   0.02, 200},