feat: funciones Python datascience, finance, cybersecurity y pipelines

Datascience: aggregate_by_group, deduplicate_entities/relations, detect_drift,
diff_entities/relations, extract_entities/relations_llm, hotness_score, melt,
merge_graphs, pivot, build_entity/relation_schema_prompt.
Finance: avellaneda_stoikov_quotes, generate_gbm_prices, generate_taker_order,
hawkes_intensity + módulo finance.py.
Cybersecurity: envelope_encrypt/decrypt + módulo cybersecurity.py.
Pipelines: extraction_pipeline, monte_carlo_market, run_market_sim.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

python/functions/datascience/melt.md

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+---
+name: melt
+kind: function
+lang: py
+domain: datascience
+version: "1.0.0"
+purity: pure
+signature: "def melt(rows: list[dict], id_vars: list[str], value_vars: list[str] | None = None, var_name: str = 'variable', value_name: str = 'value') -> list[dict]"
+description: "Inversa de pivot. Convierte columnas en filas (formato largo). Cada combinacion de id_vars + value_var genera una fila. Si value_vars es None, derrite todas las columnas no-id."
+tags: [datascience, tabular, melt, unpivot, transform, python]
+uses_functions: []
+uses_types: []
+returns: []
+returns_optional: false
+error_type: ""
+imports: []
+tested: true
+tests:
+  - "Melt basico"
+  - "Multiples id_vars"
+  - "value_vars None derrite todas las columnas no-id"
+  - "Fila con campo faltante en value_vars"
+test_file_path: "python/functions/datascience/melt_test.py"
+file_path: "python/functions/datascience/melt.py"
+---
+
+## Ejemplo
+
+```python
+rows = [{"region": "US", "q1": 10, "q2": 20}]
+melt(rows, id_vars=["region"], value_vars=["q1", "q2"])
+# [{"region": "US", "variable": "q1", "value": 10},
+#  {"region": "US", "variable": "q2", "value": 20}]
+```
+
+## Notas
+
+Funcion pura sin dependencias externas.
+Si un campo de value_vars no existe en la fila, su valor sera None.
+El parametro value_vars=None es util cuando se desconoce el schema exacto.