feat(models): Expose model memory usage

Override get_allocated_memory_bytes() in Tungsten and Aluminum
to return existing mem_allocated computed during allocate().

- Leverages utils::sizeof_vec() tracking already in place
- Enables accurate app vs FFT memory breakdown in reports

Author: ahojukka5

apps/aluminumNew/Aluminum.hpp

@@ -326,6 +326,13 @@ class Aluminum : public Model {
     fft.backward(psi_F, psi);
   }
 
+  /**
+   * @brief Calculate memory allocated by the Aluminum model
+   *
+   * @return Total allocated memory in bytes for all model fields and operators
+   */
+  size_t get_allocated_memory_bytes() const override { return mem_allocated; }
+
   /**
    * @brief Constructs an Aluminum model with the given World object.
    *

apps/tungsten/tungsten_model.hpp

@@ -382,6 +382,13 @@ class Tungsten : public Model {
     CHECK_AND_ABORT_IF_NANS(psi);
   }
 
+  /**
+   * @brief Calculate memory allocated by the Tungsten model
+   *
+   * @return Total allocated memory in bytes for all model fields and operators
+   */
+  size_t get_allocated_memory_bytes() const override { return mem_allocated; }
+
   /**
    * @brief Constructs a Tungsten model with the given World object
    *