feat: scaffold FCES-native C++ project with libtorch integration

- CMakeLists.txt with libtorch, GoogleTest, GoogleBenchmark, OpenMP, pybind11
- Header files: config, controller, population, fitness, evolution, spectral, oscillation, telemetry, optimizer
- Source implementations: controller (full micro-MLP forward pass, mutation, crossover), fitness (Welford's algorithm), oscillation (DFT), spectral (SVD rank), optimizer (sign-SGD stub)
- Tests: controller, population, fitness, optimizer (Google Test)
- Benchmarks: evolve throughput, optimizer step (Google Benchmark)
- Examples: simple optimization, PyTorch/libtorch integration
- Python extension: pybind11 bindings with setup.py
- README with architecture diagram and build instructions

include/fces/spectral.hpp

@@ -0,0 +1,53 @@
+#pragma once
+
+/**
+ * @file spectral.hpp
+ * @brief Spectral Sensor and Controller — grokking awareness via rank tracking.
+ *
+ * Port of: packages/fces/core/spectral_sensor.py + spectral_controller.py
+ */
+
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+#include <torch/torch.h>
+
+namespace fces {
+
+/**
+ * SpectralSensor — tracks the effective rank of weight matrices.
+ *
+ * Used for grokking detection: when the model transitions from
+ * memorization to generalization, the effective rank drops.
+ */
+class SpectralSensor {
+public:
+    explicit SpectralSensor(torch::nn::Module& model);
+
+    /// Track a layer's weight tensor
+    void track_layer(const std::string& name, const torch::Tensor& weight);
+
+    /// Get the global (average) effective rank
+    float get_global_rank() const;
+
+    /// Reset all tracked layers
+    void reset();
+
+private:
+    std::unordered_map<std::string, float> layer_ranks_;
+
+    /// Compute effective rank via SVD
+    static float compute_effective_rank(const torch::Tensor& weight);
+};
+
+/**
+ * SpectralController — converts spectral rank into optimizer decisions.
+ */
+class SpectralController {
+public:
+    /// Compute the spectral alpha (gating factor for rank-aware updates)
+    float compute_alpha(float global_rank, float grokking_coefficient) const;
+};
+
+}  // namespace fces