feat: funciones Python para core, cybersecurity, datascience y finance

Agrega funciones Python reutilizables organizadas por dominio:
- core: composicion funcional (pipe, compose, map, filter, reduce, etc.)
- cybersecurity: analisis de amenazas y puertos
- datascience: estadisticas y deteccion de outliers
- finance: indicadores tecnicos y analisis financiero

python/functions/core/flatten.md

@@ -0,0 +1,32 @@
+---
+name: flatten
+kind: function
+lang: py
+domain: core
+version: "1.0.0"
+purity: pure
+signature: "def flatten(xss: list) -> list"
+description: "Aplana una lista de listas un nivel, concatenando las sublistas."
+tags: [list, functional, flatten, python]
+uses_functions: []
+uses_types: []
+returns: []
+returns_optional: false
+error_type: ""
+imports: []
+tested: false
+tests: []
+test_file_path: ""
+file_path: "python/functions/core/core.py"
+---
+
+## Ejemplo
+
+```python
+result = flatten([[1, 2], [3], [4, 5]])
+# [1, 2, 3, 4, 5]
+```
+
+## Notas
+
+Funcion pura. Solo aplana un nivel de anidamiento.