feat: Implement file-based persistence for user registration

This commit introduces a file-based persistence layer to store and retrieve registered user chat IDs.

Previously, the bot used an in-memory `set` to track registered users, which was cleared on every restart. This caused the bot to lose track of all registered users, preventing them from accessing registered-only features.

This commit resolves the issue by:
- Creating a `data/registered_users.txt` file to store user chat IDs.
- Implementing a `load_registered_users` function to load the user data from the file at startup.
- Modifying the `register_user` function to append new user chat IDs to the file.
- Calling `load_registered_users` from `main.py` at startup to initialize the user state.

app/main.py

@@ -18,7 +18,10 @@ from telegram.ext import Application, Defaults, CommandHandler, ContextTypes
 # --- IMPORTAR HABILIDADES ---
 from modules.flow_builder import load_flows
 from modules.logger import log_request
-from modules.database import chat_id_exists  # Importar chat_id_exists
+from modules.database import (
+    chat_id_exists,
+    load_registered_users,
+)  # Importar chat_id_exists y load_registered_users
 from modules.ui import main_actions_keyboard
 
 from modules.rh_requests import vacaciones_handler, permiso_handler
@@ -106,6 +109,11 @@ async def menu_principal(update: Update, context: ContextTypes.DEFAULT_TYPE):
 
 
 async def post_init(application: Application):
+    """Tareas a ejecutar después de que el bot se haya inicializado."""
+    # Cargar usuarios registrados desde el archivo de persistencia.
+    # Es crucial que esto se ejecute antes de que el bot empiece a recibir updates.
+    load_registered_users()
+
     # Mantén los comandos rápidos disponibles en el menú de Telegram
     await application.bot.set_my_commands(
         [

app/modules/database.py

@@ -1,4 +1,15 @@
 import logging
+import os
+
+# --- CONFIGURACIÓN DE PERSISTENCIA ---
+# Usamos un archivo de texto para persistir los chat_id de usuarios registrados.
+# Esto es una solución temporal y ligera hasta que se implemente una base de datos.
+DATA_DIR = os.path.join(os.path.dirname(__file__), "..", "..", "data")
+USERS_FILE = os.path.join(DATA_DIR, "registered_users.txt")
+
+# Asegurarse de que el directorio de datos exista
+os.makedirs(DATA_DIR, exist_ok=True)
+
 
 # MOCK DATABASE MODULE
 # Since the actual DB is removed temporarily, this module provides mock implementations.
@@ -9,23 +20,59 @@ SessionVanityAttendance = None
 
 _REGISTERED_USERS = set()
 
+
+def load_registered_users():
+    """Carga los chat_id de usuarios registrados desde el archivo de texto."""
+    try:
+        if os.path.exists(USERS_FILE):
+            with open(USERS_FILE, "r") as f:
+                for line in f:
+                    try:
+                        _REGISTERED_USERS.add(int(line.strip()))
+                    except ValueError:
+                        logging.warning(
+                            f"[DB] Se ignoró una línea no válida en {USERS_FILE}: {line.strip()}"
+                        )
+            logging.info(
+                f"[DB] Se cargaron {len(_REGISTERED_USERS)} usuarios registrados desde {USERS_FILE}"
+            )
+        else:
+            logging.info(f"[DB] No se encontró el archivo de usuarios en {USERS_FILE}, se creará uno nuevo al primer registro.")
+    except Exception as e:
+        logging.error(f"[DB] Error al cargar usuarios registrados: {e}")
+
+
 def chat_id_exists(chat_id: int) -> bool:
     """Mock check: returns True if user is in in-memory set."""
     return int(chat_id) in _REGISTERED_USERS
 
+
 def register_user(user_data: dict) -> bool:
-    """Mock register: adds user to in-memory set."""
+    """
+    Mock register: adds user to in-memory set and appends to the persistence file.
+    """
     try:
         meta = user_data.get("meta", {})
         metadata = user_data.get("metadata", {})
         tid = meta.get("telegram_id") or metadata.get("telegram_id") or metadata.get("chat_id")
-        
+
         if tid:
-            _REGISTERED_USERS.add(int(tid))
-            logging.info(f"[MockDB] User {tid} registered in memory.")
+            chat_id = int(tid)
+            if chat_id not in _REGISTERED_USERS:
+                _REGISTERED_USERS.add(chat_id)
+                # Persistir en el archivo de texto
+                with open(USERS_FILE, "a") as f:
+                    f.write(f"{chat_id}\n")
+                logging.info(f"[DB] User {chat_id} registered in memory and persisted to file.")
+            else:
+                logging.info(f"[DB] User {chat_id} was already registered.")
             return True
-        logging.warning("[MockDB] Could not find telegram_id in user_data.")
+
+        logging.warning("[DB] Could not find telegram_id in user_data to register.")
+        return False
+    except (ValueError, TypeError) as e:
+        logging.error(f"[DB] Invalid telegram_id format: {tid}. Error: {e}")
         return False
     except Exception as e:
-        logging.error(f"[MockDB] Register error: {e}")
+        logging.error(f"[DB] Register error: {e}")
         return False