Initial import of Shirobana bot backend

Include utility modules, shared channels, prompts, read-only skills, wardrobe memory and regression tests. Externalize legacy credentials and exclude private runtime state.

tests/test_mode_config.py

@@ -0,0 +1,28 @@
+import json
+import tempfile
+import unittest
+from pathlib import Path
+from unittest.mock import mock_open, patch
+
+import identity
+from agent.modes import ModeStore
+
+
+class ModeConfigTest(unittest.TestCase):
+    def test_admin_chat_other_command_and_saved_override(self):
+        with tempfile.TemporaryDirectory() as tmp:
+            store = ModeStore(Path(tmp) / "modes.db")
+            config = json.dumps({"chat_mode": {"default": "command", "admin": "chat", "group": "command"}})
+            with patch("pathlib.Path.open", mock_open(read_data=config)), \
+                 patch.object(identity, "is_admin", side_effect=lambda uid: uid == 1):
+                self.assertEqual(store.get_mode("tg", 1), "chat")
+                self.assertEqual(store.get_mode("tg", 2), "command")
+                self.assertEqual(store.get_mode("tg", 1, 123), "command")
+                store.set_mode("tg", 2, "chat")
+                self.assertEqual(store.get_mode("tg", 2), "chat")
+                store.set_mode("tg", 1, "command")
+                self.assertEqual(store.get_mode("tg", 1), "command")
+
+
+if __name__ == "__main__":
+    unittest.main()