docs(agents): scaffold docs/agents/ skill config files

- docs/agents/issue-tracker.md — GitHub, gsd-build/get-shit-done, .envrc token required
- docs/agents/triage-labels.md — confirmed=AFK-ready, approved-*=human-ready, needs-reproduction=needs-info
- docs/agents/domain.md — single-context, CONTEXT.md sections explained
- CLAUDE.md — fix stale triage label (needs-maintainer-review doesn't exist),
  fix stale domain note ('neither exists yet'), add .envrc token reminder to issue tracker summary

docs/agents/domain.md

@@ -0,0 +1,32 @@
+# Domain Docs
+
+How engineering skills consume this repo's domain documentation.
+
+## Layout: single-context
+
+```
+/
+├── CONTEXT.md          ← domain glossary + recurring PR rules + workflow learnings
+├── docs/adr/           ← architectural decisions
+│   ├── 0001-dispatch-policy-module.md
+│   └── 0002-command-contract-validation-module.md
+└── ...
+```
+
+## Before exploring, read these
+
+1. **`CONTEXT.md`** at the repo root — domain terms, module names, recurring PR mistakes, workflow learnings. Read in full before naming anything or proposing architecture changes.
+2. **`docs/adr/`** — read ADRs relevant to the area you're working in before proposing structural changes. If your output contradicts an ADR, surface it explicitly:
+   > *Contradicts ADR-0002 — but worth reopening because…*
+
+If either file doesn't exist yet, proceed silently.
+
+## Use the glossary's vocabulary
+
+When naming modules, writing issue titles, test descriptions, or commit messages — use terms as defined in `CONTEXT.md`. Don't drift to synonyms. If you need a concept that isn't in the glossary, note it for `/grill-with-docs` rather than inventing language.
+
+## CONTEXT.md sections
+
+- **Domain terms** — canonical module names and seam vocabulary (Dispatch Policy Module, Command Contract Validation Module, etc.)
+- **Recurring PR mistakes** — CodeRabbit findings that recur; check before writing tests, shell scripts, changesets, or docs
+- **Workflow learnings** — patterns learned from triage + PR cycles; check before writing new command/workflow files or test paths