feat: login time window rules (EPIC_000014)

- Implemented RuleManager and JSON storage
- Added background enforcement scheduler
- Added Web UI for rule management at /ui/rules
- Bumped version to 0.3.0

backend/settings.py

@@ -57,6 +57,9 @@ class Settings:
         self.update_log_file: str = os.getenv(
             "SKD_UPDATE_LOG_FILE", "/var/lib/skd/update_logs.jsonl"
         )
+        self.rules_file: str = os.getenv(
+            "SKD_RULES_FILE", "/var/lib/skd/rules.json"
+        )
         # Paths/tools
         self.notify_send_path: str = os.getenv("SKD_NOTIFY_SEND_PATH", "notify-send")
         self.sound_player: str = os.getenv("SKD_SOUND_PLAYER", "paplay")