docs: update CLAUDE.md agent skills block (was gitignored)

CLAUDE.md

@@ -0,0 +1,31 @@
+## GitHub access
+
+**Always** set `GITHUB_TOKEN` from `.envrc` before any `gh` CLI call:
+
+```bash
+export GITHUB_TOKEN=$(grep GITHUB_TOKEN .envrc | cut -d\' -f2)
+```
+
+Or prefix every `gh` command:
+
+```bash
+GITHUB_TOKEN=$(grep GITHUB_TOKEN .envrc | cut -d\' -f2) gh issue create ...
+```
+
+**Never** use the ambient `gh auth` session — it resolves to enterprise credentials that cannot access this repo. The `.envrc` token is the only credential authorised for `gsd-build/get-shit-done`.
+
+---
+
+## Agent skills
+
+### Issue tracker
+
+Issues live in GitHub Issues (`gsd-build/get-shit-done`). Always use the `.envrc` token — never the ambient `gh auth` session. See `docs/agents/issue-tracker.md`.
+
+### Triage labels
+
+Custom label mapping: `confirmed` = AFK-agent-ready (bugs); `approved-enhancement` / `approved-feature` = human-ready (enhancements/features); `needs-reproduction` = waiting on reporter. See `docs/agents/triage-labels.md`.
+
+### Domain docs
+
+Single-context repo — `CONTEXT.md` + `docs/adr/` at the root. See `docs/agents/domain.md`.