Server isolation and detailed errors

Isolated the JsonServer to server.py inside protocols/json

Added specific errors for server startup timeout and server startup
failed

Refactored errors for Core to CoreError generic and refactored
StateError to CoreStateMismatchError derived from CoreError

src/dynalab_core/errors.py

@@ -2,6 +2,27 @@
 # Copyright (C) 2026 Association Exergie <association.exergie@gmail.com>
 # SPDX-License-Identifier: GPL-3.0-or-later
 
+# Core error declarations
+class CoreError(Exception):
+    """DynaLab Core error."""
 
-class StateError(Exception):
+
+class CoreStateMismatchError(CoreError):
     """DynaLab Core state error."""
+
+
+# JsonServer error declarations
+class JsonServerError(Exception):
+    """Generic JsonServer Error"""
+
+
+class JsonServerTimeoutError(JsonServerError):
+    """JsonServer timed out"""
+
+
+class JsonServerStartupError(JsonServerError):
+    """JsonServer crashed on startup"""
+
+    def __init__(self, error: Exception) -> None:
+        self.error = error
+        super().__init__(f"JSON server failed to start: {error}")