feat: initial fluxer codebase import

fluxer_devops/cassandra/migrations/20251212120000_user_contact_change_logs.cql

@@ -0,0 +1,11 @@
+CREATE TABLE IF NOT EXISTS fluxer.user_contact_change_logs (
+    user_id bigint,
+    event_id timeuuid,
+    field text,
+    old_value text,
+    new_value text,
+    reason text,
+    actor_user_id bigint,
+    event_at timestamp,
+    PRIMARY KEY ((user_id), event_id)
+) WITH CLUSTERING ORDER BY (event_id DESC);