feat: add LOGGER.ENABLED toggle to disable application logging

When LOGGER.ENABLED is false, setup_logging attaches only a NullHandler
so legacy configs without the key keep current behavior. Document the
option in EN/ES configuration guides and example YAML templates.

adn-parrot.example.yaml

@@ -27,6 +27,7 @@ REPORTS:
   REPORT_CLIENTS: "127.0.0.1"
 
 LOGGER:
+  # ENABLED: false   # omit or true = normal; false = no console/file logs (NullHandler)
   LOG_FILE: /var/log/adn-server/parrot.log
   LOG_HANDLERS: file-timed
   LOG_LEVEL: DEBUG

adn-server.example.yaml

@@ -25,6 +25,7 @@ REPORTS:
   REPORT_CLIENTS: "127.0.0.1"
 
 LOGGER:
+  # ENABLED: false   # omit or true = normal; false = no console/file logs (NullHandler)
   LOG_FILE: /var/log/adn-server/adn-server.log
   LOG_HANDLERS: file-timed
   LOG_LEVEL: INFO

docs/en/server/user-guide/configuration.md

@@ -163,6 +163,7 @@ Implemented in `infrastructure/logging_config.py` (`setup_logging`). Values are
 
 | Key | Meaning |
 |-----|---------|
+| **ENABLED** | **`true`** (default when omitted) — normal logging. **`false`** — disable application log output (no console or file handlers; `NullHandler` only). Legacy configs without this key behave as today. |
 | **LOG_HANDLERS** | Comma-separated list of handler **tokens** (whitespace around commas is fine). Each token selects outputs; you can combine several. Recognised values: **`console-timed`** or **`console`** — log to **stderr** with format `LEVEL asctime message`; **`file-timed`** or **`file`** — log to **LOG_FILE** with the same format (UTF-8). **Default** if omitted: `console-timed`. Examples: `console-timed` only; `file-timed` only; `console-timed,file-timed` for both console and file. |
 | **LOG_FILE** | Path used when **`file-timed`** or **`file`** is in **LOG_HANDLERS**. If missing, the code defaults to `/dev/null`. If the path is **`/dev/null`**, file handlers are **not** attached even if listed. If the file cannot be opened (permissions, missing directory), a warning is written to stderr and logging continues without that file handler. |
 | **LOG_LEVEL** | Root logger level: **`DEBUG`**, **`INFO`**, **`WARNING`**, **`ERROR`**, **`CRITICAL`** (case-insensitive; default **INFO**). Unknown names fall back to **INFO**. You can override at startup with **`python adn-server.py --logging LEVEL`** (same names). A custom **`TRACE`** level is registered for occasional `logger.trace(...)` calls; use **`DEBUG`** for verbose diagnostics in normal operation. |

docs/es/server/user-guide/configuration.md

@@ -163,6 +163,7 @@ Implementado en `infrastructure/logging_config.py` (`setup_logging`). Los valore
 
 | Clave | Significado |
 |-------|-------------|
+| **ENABLED** | **`true`** (por defecto si se omite) — logging normal. **`false`** — desactiva la salida de logs de la aplicación (sin consola ni fichero; solo `NullHandler`). Las configs antiguas sin esta clave no cambian. |
 | **LOG_HANDLERS** | Lista separada por comas de **tokens** de manejador (espacios alrededor de las comas están bien). Cada token elige salidas; puedes combinar varios. Valores reconocidos: **`console-timed`** o **`console`** — log a **stderr** con formato `LEVEL asctime message`; **`file-timed`** o **`file`** — log a **LOG_FILE** con el mismo formato (UTF-8). **Por defecto** si falta: `console-timed`. Ejemplos: solo `console-timed`; solo `file-timed`; `console-timed,file-timed` para consola y fichero. |
 | **LOG_FILE** | Ruta usada cuando **`file-timed`** o **`file`** está en **LOG_HANDLERS**. Si falta, el código usa por defecto `/dev/null`. Si la ruta es **`/dev/null`**, los manejadores de fichero **no** se adjuntan aunque estén listados. Si no se puede abrir el fichero (permisos, directorio inexistente), se escribe un aviso a stderr y el logging continúa sin ese manejador de fichero. |
 | **LOG_LEVEL** | Nivel del logger raíz: **`DEBUG`**, **`INFO`**, **`WARNING`**, **`ERROR`**, **`CRITICAL`** (sin distinguir mayúsculas; por defecto **INFO**). Nombres desconocidos caen en **INFO**. Puedes sobrescribir al arranque con **`python adn-server.py --logging LEVEL`** (mismos nombres). Hay un nivel personalizado **`TRACE`** registrado para llamadas ocasionales `logger.trace(...)`; usa **`DEBUG`** para diagnóstico detallado en operación normal. |

src/adn_server/infrastructure/logging_config.py

@@ -31,6 +31,18 @@ from functools import partial, partialmethod
 from typing import Any
 
 
+def logging_enabled(log_config: dict[str, Any]) -> bool:
+    """LOGGER.ENABLED — default True when omitted (legacy configs unchanged)."""
+    if "ENABLED" not in log_config:
+        return True
+    val = log_config.get("ENABLED")
+    if isinstance(val, bool):
+        return val
+    if isinstance(val, str):
+        return val.strip().lower() in ("1", "true", "yes", "on")
+    return bool(val)
+
+
 def reopen_file_handlers(logger: logging.Logger | None = None) -> int:
     """Reopen all :class:`logging.FileHandler` streams on *logger* (default: root).
 
@@ -61,11 +73,22 @@ def reopen_file_handlers(logger: logging.Logger | None = None) -> int:
 
 
 def setup_logging(log_config: dict[str, Any]) -> logging.Logger:
-    """Configure logging from CONFIG['LOGGER']. Returns root logger."""
+    """Configure logging from CONFIG['LOGGER']. Returns application logger."""
+    log_name = log_config.get("LOG_NAME", "ADN")
+
+    if not logging_enabled(log_config):
+        logging.basicConfig(
+            level=logging.CRITICAL,
+            handlers=[logging.NullHandler()],
+            force=True,
+        )
+        logger = logging.getLogger(log_name)
+        logger.setLevel(logging.CRITICAL)
+        return logger
+
     level = getattr(logging, (log_config.get("LOG_LEVEL", "INFO")).upper(), logging.INFO)
     log_file = log_config.get("LOG_FILE", "/dev/null")
     handlers_cfg = log_config.get("LOG_HANDLERS", "console-timed").strip().split(",")
-    log_name = log_config.get("LOG_NAME", "ADN")
 
     logging.TRACE = 5
     logging.addLevelName(logging.TRACE, "TRACE")