feat: add Python core and infra functions — PWA, geocoding, POI matching

Nuevas funciones Python: build_guide_prompt, generate_pwa_manifest,
generate_service_worker, match_pois_to_interests (core), nominatim_reverse_geocode,
ollama_chat, overpass_nearby_pois (infra). Incluye tests unitarios.

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

python/functions/infra/ollama_chat.py

@@ -0,0 +1,70 @@
+"""Envía una solicitud de chat completion a Ollama (API local compatible con OpenAI)."""
+
+import json
+import urllib.request
+import urllib.error
+from typing import Any
+
+
+def ollama_chat(
+    messages: list[dict],
+    model: str = "llama3.1:8b",
+    base_url: str = "http://localhost:11434",
+    temperature: float = 0.7,
+    max_tokens: int = 1024,
+) -> dict:
+    """Envía una solicitud de chat completion a Ollama.
+
+    Args:
+        messages: Lista de mensajes con formato {"role": "system"|"user"|"assistant", "content": str}.
+        model: Nombre del modelo Ollama a usar.
+        base_url: URL base de la instancia Ollama.
+        temperature: Temperatura de generación (0.0 - 1.0).
+        max_tokens: Número máximo de tokens a generar.
+
+    Returns:
+        Dict con content, model, total_duration_ms y eval_count.
+
+    Raises:
+        RuntimeError: Si Ollama no está corriendo o retorna error HTTP.
+    """
+    url = f"{base_url}/api/chat"
+    payload = {
+        "model": model,
+        "messages": messages,
+        "stream": False,
+        "options": {
+            "temperature": temperature,
+            "num_predict": max_tokens,
+        },
+    }
+    body = json.dumps(payload).encode("utf-8")
+    req = urllib.request.Request(
+        url,
+        data=body,
+        headers={"Content-Type": "application/json"},
+        method="POST",
+    )
+    try:
+        with urllib.request.urlopen(req, timeout=60) as resp:
+            raw = resp.read()
+    except urllib.error.URLError as exc:
+        reason = str(exc.reason) if hasattr(exc, "reason") else str(exc)
+        if "connection refused" in reason.lower() or "111" in reason:
+            raise RuntimeError(f"Ollama no está corriendo en {base_url}") from exc
+        raise RuntimeError(f"Error de conexión con Ollama: {reason}") from exc
+    except urllib.error.HTTPError as exc:
+        raise RuntimeError(f"Ollama retornó HTTP {exc.code}: {exc.reason}") from exc
+
+    response: dict[str, Any] = json.loads(raw)
+    content: str = response["message"]["content"]
+    total_duration_ns: int = response.get("total_duration", 0)
+    total_duration_ms: int = int(total_duration_ns / 1_000_000)
+    eval_count: int = response.get("eval_count", 0)
+
+    return {
+        "content": content,
+        "model": response.get("model", model),
+        "total_duration_ms": total_duration_ms,
+        "eval_count": eval_count,
+    }