new calculation approach with unique sessions, new API endpoint to get list of active sessions, fix for UNDEF user, UI and Back to support certificate management still under development

APP/db.py

@@ -67,6 +67,20 @@ class DatabaseManager:
             ''')
             cursor.execute('CREATE INDEX IF NOT EXISTS idx_usage_ts ON usage_history(timestamp)')
 
+            # 2.1 Active Sessions (Temporary state table)
+            cursor.execute('''
+            CREATE TABLE IF NOT EXISTS active_sessions (
+                client_id INTEGER,
+                common_name TEXT,
+                real_address TEXT,
+                bytes_received INTEGER,
+                bytes_sent INTEGER,
+                connected_since TIMESTAMP,
+                last_seen TIMESTAMP,
+                FOREIGN KEY (client_id) REFERENCES clients (id)
+            )
+            ''')
+
             # 3. Aggregated Stats Tables
             tables = ['stats_5min', 'stats_15min', 'stats_hourly', 'stats_6h', 'stats_daily']