Add setup-matt-pocock-skills; rename github-triage to triage; migrate engineering skills to vague prose

Engineering skills no longer hard-code GitHub or specific label strings.
A new setup skill scaffolds an `## Agent skills` block in
AGENTS.md/CLAUDE.md plus `docs/agents/` so each repo can declare its own
backlog backend, triage label vocabulary, and domain doc layout. Skills
that need the mapping (to-issues, to-prd, triage) point at the setup
skill; skills that only soften with it (diagnose, tdd,
improve-codebase-architecture, zoom-out) stay vague. ADR-0001 records
the split.

Closes #88, #89.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

skills/engineering/grill-with-docs/DOMAIN-AWARENESS.md

@@ -1,51 +0,0 @@
-# Domain Awareness
-
-Consumer rules for any skill that explores a codebase. Producer rules (writing `CONTEXT.md`, offering ADRs) live in [SKILL.md](./SKILL.md).
-
-## Before exploring, read these
-
-- **`CONTEXT.md`** at the repo root, or
-- **`CONTEXT-MAP.md`** at the repo root if it exists — it points at one `CONTEXT.md` per context. Read each one relevant to the topic.
-- **`docs/adr/`** — read ADRs that touch the area you're about to work in. In multi-context repos, also check `src/<context>/docs/adr/` for context-scoped decisions.
-
-If any of these files don't exist, **proceed silently**. Don't flag their absence; don't suggest creating them upfront. The producer skill (`/grill-with-docs`) creates them lazily when terms or decisions actually get resolved.
-
-## File structure
-
-Single-context repo (most repos):
-
-```
-/
-├── CONTEXT.md
-├── docs/adr/
-│   ├── 0001-event-sourced-orders.md
-│   └── 0002-postgres-for-write-model.md
-└── src/
-```
-
-Multi-context repo (presence of `CONTEXT-MAP.md` at the root):
-
-```
-/
-├── CONTEXT-MAP.md
-├── docs/adr/                          ← system-wide decisions
-└── src/
-    ├── ordering/
-    │   ├── CONTEXT.md
-    │   └── docs/adr/                  ← context-specific decisions
-    └── billing/
-        ├── CONTEXT.md
-        └── docs/adr/
-```
-
-## Use the glossary's vocabulary
-
-When your output names a domain concept (in an issue title, a refactor proposal, a hypothesis, a test name), use the term as defined in `CONTEXT.md`. Don't drift to synonyms the glossary explicitly avoids.
-
-If the concept you need isn't in the glossary yet, that's a signal — either you're inventing language the project doesn't use (reconsider) or there's a real gap (note it for `/grill-with-docs`).
-
-## Flag ADR conflicts
-
-If your output contradicts an existing ADR, surface it explicitly rather than silently overriding:
-
-> _Contradicts ADR-0007 (event-sourced orders) — but worth reopening because…_