first commit

internal/session/keys.go

@@ -0,0 +1,10 @@
+package session
+
+// UserIDKey is the string key under which we store the logged-in user's
+// numeric ID inside the session (via sessions.Put(ctx, UserIDKey, id)).
+//
+// This constant exists so the key is spelled exactly once, in one place -
+// every other file that touches this key (login, logout, the auth
+// middleware) imports this constant instead of retyping the raw string
+// "user_id", which would risk a typo silently breaking authentication.
+const UserIDKey = "user_id"