feat: funciones Python infra y tipos Python (core, datascience, infra)

Infra: cache_to_file, cache_to_sqlite, http_download_file, http_get_json,
http_post_json, read_file_with_encoding, safe_extract_zip, scan_directory,
setup_logger, normalize_zip_filenames.
Tipos: 30+ tipos core (agent_action, context, task, message, parse_result...),
6 tipos datascience (entity_candidate, extraction_result...), 2 tipos infra.

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

python/functions/infra/http_download_file.md

@@ -0,0 +1,40 @@
+---
+name: http_download_file
+kind: function
+lang: py
+domain: infra
+version: "1.0.0"
+purity: impure
+signature: "http_download_file(url: str, dest_path: str, headers: dict[str, str] | None = None, timeout: float = 120.0, chunk_size: int = 8192) -> dict"
+description: "Descarga un archivo por HTTP en streaming (sin cargar todo en memoria). Crea directorios intermedios si no existen. Retorna dict con path, size_bytes y content_type."
+tags: [http, download, file, streaming, network, stdlib, infra]
+uses_functions: []
+uses_types: []
+returns: []
+returns_optional: false
+error_type: "error_go_core"
+imports: ["os", "urllib.error", "urllib.request"]
+tested: true
+tests:
+  - "mock de descarga con contenido binario"
+  - "directorio destino creado automaticamente"
+  - "retorno con size correcto"
+  - "timeout configurado en el request"
+test_file_path: "python/functions/infra/http_download_file_test.py"
+file_path: "python/functions/infra/http_download_file.py"
+---
+
+## Ejemplo
+
+```python
+result = http_download_file(
+    "https://example.com/report.pdf",
+    dest_path="/tmp/reports/report.pdf",
+    timeout=60.0,
+)
+print(f"Downloaded {result['size_bytes']} bytes to {result['path']}")
+```
+
+## Notas
+
+Solo usa stdlib (urllib, os). La descarga se hace en chunks de `chunk_size` bytes para evitar consumo de memoria con archivos grandes. El timeout de 120s por defecto es mayor que http_get_json porque los archivos pueden ser pesados. Los directorios intermedios se crean con os.makedirs(exist_ok=True).