chore(agents): point Matt Pocock skills at the beads issue tracker

The engineering skills (to-tickets, triage, spec, wayfinder) need to know
where issues live for this repo. It is not the Gitea forge remote; it is
bd/beads, which AGENTS.md already mandates for all task tracking.

Adds docs/agents/issue-tracker.md (bd commands and wayfinding mapping),
docs/agents/triage-labels.md (five canonical roles kept as-is, applied
with bd tag / bd label add), docs/agents/domain.md (single-context
layout: CONTEXT.md plus docs/adr/ at the root), and an 'Agent skills'
index block in AGENTS.md. The pre-existing staged deletion of CLAUDE.md
is left out of this commit and stays in the index.

AGENTS.md

@@ -375,6 +375,20 @@ git add packages/my-tool README.md
 bd close <id>         # Mark task as complete
 ```
 
+## Agent skills
+
+### Issue tracker
+
+Issues live in the beads database (`.beads/`, driven by the `bd` CLI), synced through `git push`. The Gitea remote is not the issue tracker. See `docs/agents/issue-tracker.md`.
+
+### Triage labels
+
+The five canonical triage roles keep their default names, applied as `bd` labels. See `docs/agents/triage-labels.md`.
+
+### Domain docs
+
+Single-context layout: `CONTEXT.md` plus `docs/adr/` at the repo root. See `docs/agents/domain.md`.
+
 <!-- BEGIN BEADS INTEGRATION v:1 profile:minimal hash:ca08a54f -->
 ## Beads Issue Tracker