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/Credenciales/ollama_credencial.py

@@ -0,0 +1,20 @@
+from domains.Security.GenerarIDs import GeneradorIDUnico
+
+class OllamaCredencial:
+    def __init__(self, titulo: str, base_url: str = "http://localhost:11434", id: str = None):
+        """
+        :param titulo: Nombre descriptivo para esta credencial de Ollama.
+        :param base_url: URL base donde está corriendo el servidor de Ollama (por defecto: localhost).
+        """
+        self.id = id if id is not None else GeneradorIDUnico("OLLA").generar()
+        self.titulo = titulo
+        self.base_url = base_url.rstrip("/")
+
+    def get_headers(self) -> dict:
+        """
+        Retorna encabezados para autenticación si se requiere en el futuro.
+        Por defecto, Ollama local no usa headers especiales.
+        """
+        return {
+            "Content-Type": "application/json"
+        }