feat: enhance jupyter notebook functions with auto-init and kernel management

Auto-create notebooks y sesiones en jupyter_exec (append y cell).
Auto-create en jupyter_write (append_code, append_markdown, batch).
Nuevos subcomandos cleanup y shutdown-all en jupyter_kernel.
README.md renombrado a README.txt para evitar error de parseo del indexer.

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

python/functions/notebook/jupyter_write.py

@@ -30,6 +30,35 @@ def _resolve_collab_username(server_url: str, token: str) -> str:
         return "Anonymous"
 
 
+# ---------------------------------------------------------------------------
+# Helpers internos
+# ---------------------------------------------------------------------------
+
+
+def _notebook_exists(notebook_path: str, server_url: str, token: str) -> bool:
+    """Comprueba si un notebook existe en el servidor Jupyter via HEAD /api/contents."""
+    headers = {"Accept": "application/json"}
+    if token:
+        headers["Authorization"] = f"token {token}"
+    check_url = f"{server_url}/api/contents/{notebook_path}"
+    req = Request(check_url, headers=headers, method="HEAD")
+    try:
+        with urlopen(req, timeout=5):
+            return True
+    except HTTPError as e:
+        if e.code == 404:
+            return False
+        raise
+
+
+def _auto_create_notebook(notebook_path: str, server_url: str, token: str) -> bool:
+    """Crea el notebook si no existe. Retorna True si fue creado."""
+    if not _notebook_exists(notebook_path, server_url, token):
+        jupyter_create_notebook(notebook_path, server_url=server_url, token=token)
+        return True
+    return False
+
+
 # ---------------------------------------------------------------------------
 # Helpers internos async
 # ---------------------------------------------------------------------------
@@ -42,6 +71,7 @@ async def _append_cell(
     server_url: str,
     token: str,
 ) -> dict:
+    _auto_create_notebook(notebook_path, server_url, token)
     ws_url = get_jupyter_notebook_websocket_url(
         server_url=server_url,
         token=token,
@@ -139,6 +169,7 @@ async def _batch_write(
     token: str,
 ) -> dict:
     """Anade multiples celdas en una sola conexion WebSocket."""
+    _auto_create_notebook(notebook_path, server_url, token)
     ws_url = get_jupyter_notebook_websocket_url(
         server_url=server_url,
         token=token,