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/postgres_credencial.py

@@ -0,0 +1,18 @@
+from domains.Security.GenerarIDs import GeneradorIDUnico
+
+class PostgresCredencial:
+    def __init__(self, titulo: str, host: str, port: int, dbname: str, user: str, password: str, id: str = None):
+        self.id = id if id is not None else GeneradorIDUnico("PGCR").generar()
+        self.titulo = titulo
+        self.host = host
+        self.port = port
+        self.dbname = dbname
+        self.user = user
+        self.password = password
+
+        
+    def get_uri(self) -> str:
+        """
+        Retorna una URI de conexión para PostgreSQL.
+        """
+        return f"postgresql://{self.user}:{self.password}@{self.host}:{self.port}/{self.dbname}"