docs: add agent guidance and permission research docs

- add AGENTS.md and docs for issue tracker, triage labels, and domain docs
- add CONTEXT.md glossary for the permission authorization domain
- add research report on context ownership for forwarded bash asks
- ignore .pi-subagents and .codegraph directories
- remove pi-permission-ai-judge from settings packages

AGENTS.md

@@ -0,0 +1,17 @@
+# AGENTS.md
+
+Guidance for AI agents working in this repo.
+
+## Agent skills
+
+### Issue tracker
+
+Issues are tracked as Plane work items in the `pi-extensions` (`PIEXTENSIO`) project, via the Plane MCP tools. See `docs/agents/issue-tracker.md`.
+
+### Triage labels
+
+Five canonical triage roles map to labels of the same name (`needs-triage`, `needs-info`, `ready-for-agent`, `ready-for-human`, `wontfix`). See `docs/agents/triage-labels.md`.
+
+### Domain docs
+
+Single-context: one `CONTEXT.md` + `docs/adr/` at the repo root. See `docs/agents/domain.md`.