chore(aiwg): adopt shared BT6 maintainer workflow (#148)

* docs(policy): allow low-impact contributor courtesy cleanup

* chore(aiwg): migrate to shared BT6 maintainer plugin

* chore: reconcile delivery validation

.gitignore

@@ -57,14 +57,23 @@ bench/nyu/
 scripts/.export-denylist.local
 
 # --- project-local AIWG bundle source ---
-# Keep runtime/generated AIWG workspace state local. Only project-local addon
-# source is publishable.
+# Keep runtime/generated AIWG workspace state local. Project-local addon/plugin
+# source and the BT6 repository profile/lock are publishable.
 !.aiwg/
 .aiwg/*
+.aiwg/working/
 !.aiwg/addons/
 !.aiwg/addons/**
+!.aiwg/plugins/
+!.aiwg/plugins/**
+!.aiwg/bt6-maintainer.yaml
+!.aiwg/bt6-maintainer.lock.json
 
 server.pid
 
 # vitest v8 coverage output
 coverage/
+
+# Agentic provider conventional dirs (generated by aiwg use, not authored)
+.codex/
+.agents/