feat: Multiple UI improvements and new server log functionality

- Add Server Log tab with DataTable display of server activity logs

- Fix keyboard navigation bug in agents tab

- Add execution history viewer for selected agents

- Improve policy tree widget functionality by adding single device operations

- Integrate logging notifications into TUI
  - Add TextualNotificationHandler to setup.py
  - Display ERROR/WARNING/CRITICAL logs as toast notifications
  - Remove terminal output to prevent interference with TUI
  - Logs still written to Loxide.log file

closes #45

services/API.py

@@ -351,6 +351,14 @@ class AirlockAPIWrapper:
         result = self._post("/v1/getexechistory", payload)
         return result["response"]["exechistory"]
 
+    def server_logs(self, checkpoint: str | None = None) -> str:
+        """Retrieves Server Activity History Logs."""
+        payload = {}
+        if checkpoint is not None:
+            payload["checkpoint"] = checkpoint
+        result = self._post("/v1/logging/svractivities?checkpoint", payload)
+        return result["response"]["svractivities"]
+
 
 """
 from services.API import AirlockAPIWrapper