feat: Implement main application shell with navigation and color scheme toggle

- Added Appshell component with responsive navbar and main content area
- Integrated ColorSchemeToggle for light/dark mode switching
- Created Welcome component with styled title and introductory text
- Developed ChatPage for LLM interaction with WebSocket support
- Implemented Biblioteca for managing notes with rich text editor
- Added LoginPage for user authentication with error handling
- Introduced MessageList and MessageBubble components for chat messages
- Styled components with CSS modules for consistent design

domains/Llms/Memory/Base_MemoryConv.py

@@ -0,0 +1,36 @@
+from abc import ABC, abstractmethod
+from typing import Literal
+
+class MemoryConvABC(ABC):
+    """
+    Interfaz abstracta para memorias de conversación multi-turno.
+    """
+
+    def __init__(self, k: int = 10):
+        """
+        :param k: Número máximo de turnos (pares user/assistant) a retornar.
+        """
+        self.k = k
+
+    @abstractmethod
+    def guardar_turno(self, rol: Literal["user", "assistant"], contenido: str) -> None:
+        """
+        Guarda un mensaje de un turno de conversación.
+        Se guarda secuencialmente y se asume que el orden es respetado.
+        """
+        pass
+
+    @abstractmethod
+    def cargar_historial_chat(self) -> list[dict]:
+        """
+        Devuelve los últimos `k*2` mensajes como lista de dicts tipo chat:
+        [{"role": "user", "content": "..."}, {"role": "assistant", "content": "..."}]
+        """
+        pass
+
+    @abstractmethod
+    def limpiar(self) -> None:
+        """
+        Limpia completamente la memoria.
+        """
+        pass