feat(v0.3.0): API Keras, Adam/RMSprop, callbacks, BatchNorm

BREAKING CHANGE: refactor mayor de la librería.

Nuevo:
- Optimizers: Adam, RMSprop, AdaGrad + gradient clipping (clip_norm/clip_value)
- Layer: BatchNormalization con running stats
- Callbacks: EarlyStopping, ModelCheckpoint, ReduceLROnPlateau, History
- Regularizers: L1, L2, L1L2 sobre kernels
- Initializers: HeNormal, XavierNormal/Uniform, Zeros, Ones
- Metrics: BinaryAccuracy, CategoricalAccuracy, R2Score, RMSE, MAE
- Activations: ELU, Tanh con caching del forward
- Losses: Huber, MAE, SparseCategoricalCrossEntropy
- Utils: train_test_split, to_categorical, normalize, standardize

API estilo Keras:
- model.compile(optimizer, loss, metrics)
- model.fit(... validation_split, callbacks, verbose)
- model.evaluate(), predict_classes(), summary()
- Aceptación por string: optimizer='adam', loss='bce', activation='relu'
- Inferencia automática de input_size en capas posteriores

Producción:
- save_weights/load_weights en .npz portable
- get_weights/set_weights para serving custom
- Logger estructurado, verbose 0/1/2

Tests:
- 51 tests cubriendo todos los componentes
- test_gradient_check.py valida backprop con diferencias finitas
- CI matriz Python 3.8/3.10/3.12

Fix:
- MSE.derivative ahora divide por y.size (consistente con np.mean)

Migración: modelos .pkl previos no son compatibles. Re-entrena
y guarda con save_weights('.npz') para portabilidad futura.

Author: elJulioDev

.github/workflows/python-app.yml

@@ -2,23 +2,26 @@ name: Python application
 
 on:
   push:
-    branches: [ "main" ]
+    branches: ["main"]
   pull_request:
-    branches: [ "main" ]
+    branches: ["main"]
 
 jobs:
   build:
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ["3.8", "3.10", "3.12"]
     steps:
-    - uses: actions/checkout@v3
-    - name: Set up Python 3.10
-      uses: actions/setup-python@v3
-      with:
-        python-version: "3.10"
-    - name: Install dependencies
-      run: |
-        python -m pip install --upgrade pip
-        pip install -r requirements.txt
-    - name: Test with unittest
-      run: |
-        python -m unittest discover tests
+      - uses: actions/checkout@v4
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -r requirements.txt
+      - name: Test with unittest
+        run: |
+          python -m unittest discover tests -v

.gitignore

@@ -1,11 +1,27 @@
-# Python caches
+# Python
 __pycache__/
 *.py[cod]
+*.egg-info/
+*.egg
+build/
+dist/
 
-# Entornos virtuales
+# Virtual envs
 venv/
 env/
 .env
+.venv/
 
-# Configuración de entorno
-.env
+# IDE
+.vscode/
+.idea/
+*.swp
+
+# Testing / coverage
+.coverage
+.pytest_cache/
+htmlcov/
+
+# Modelos guardados
+*.pkl
+*.npz