feat(observability): logging JSON estructurado con structlog y trace_id

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tests/unit/test_logging.py

@@ -0,0 +1,30 @@
+"""Tests de logging estructurado."""
+
+from __future__ import annotations
+
+import json
+
+import structlog
+
+from agentforge_core.observability.logging import bind_trace_id, configure_logging
+
+
+def test_configure_logging_emite_json(capsys) -> None:  # type: ignore[no-untyped-def]
+    configure_logging(level="INFO")
+    log = structlog.get_logger()
+    log.info("hola", clave="valor")
+    captured = capsys.readouterr()
+    line = captured.out.strip().splitlines()[-1]
+    parsed = json.loads(line)
+    assert parsed["event"] == "hola"
+    assert parsed["clave"] == "valor"
+
+
+def test_bind_trace_id_aparece_en_logs(capsys) -> None:  # type: ignore[no-untyped-def]
+    configure_logging(level="INFO")
+    bind_trace_id("trace-abc-123")
+    log = structlog.get_logger()
+    log.info("evento")
+    line = capsys.readouterr().out.strip().splitlines()[-1]
+    parsed = json.loads(line)
+    assert parsed["trace_id"] == "trace-abc-123"