feat: add maintenance module for message deletion and related utilities

feat: implement tests for maintenance functions and dashboard interactions
feat: add timezone and country tests for thctime module

tests/test_main_scheduler.py

@@ -0,0 +1,25 @@
+import main
+
+
+def test_main_exits_quickly(monkeypatch):
+    monkeypatch.setattr(main, "send_notification", lambda x: None)
+    monkeypatch.setattr(main, "start_dashboard", lambda: None)
+    monkeypatch.setattr(main.schedule, "run_pending", lambda: (
+        _ for _ in ()).throw(KeyboardInterrupt()))
+    monkeypatch.setattr(main.time, "sleep", lambda s: None)
+    monkeypatch.setenv("DISCORD_WEBHOOK_URL", "http://example.com/webhook")
+    main.WEBHOOK_URL = "http://example.com/webhook"
+
+    main.main()
+
+
+def test_get_next_scheduled_event():
+    now = main.datetime(2025, 1, 1, 10, 14, 30)
+    nxt = main.get_next_scheduled_event(now)
+    assert nxt["type"] == "reminder"
+    assert nxt["at"].hour == 10 and nxt["at"].minute == 15
+
+    now = main.datetime(2025, 1, 1, 10, 50, 1)
+    nxt = main.get_next_scheduled_event(now)
+    assert nxt["type"] == "reminder"
+    assert nxt["at"].hour == 11 and nxt["at"].minute == 15