docs: portable runbook and Diataxis index (#27)

Public face is a product, not a laptop tool. Run steps live in
docs/runbook.md; decisions D3/D6/D14/D15/D17/D18 stay in the docs index.

docs/README.md

@@ -1,16 +1,34 @@
-# 2dph (deductionphile)
+---
+type: reference
+status: current
+related:
+  - docs/runbook.md
+  - docs/design.md
+  - PLAN.md
+---
 
-Evidence-first knowledge graph + hybrid RAG over the operational
-Brain/ops/eSlider stack. Facts need proof or they are
+# 2dph docs (Diataxis)
+
+Evidence-first knowledge graph. Facts need proof or they are
 `(not confirmed)`.
 
-- [PLAN.md](../PLAN.md) — decisions, execution order, open questions (v2)
-- [design](design.md) — schema, deduction model, sources
-- [reasoner](reasoner.md) — D18 CPU bake-off (Qwen3.5-9B vs Bonsai / Qwen3.6-27B)
-- [Gitea issues](https://git.produktor.io/eSlider/2dph/issues) — work board (origin)
+| Type | Doc |
+|------|-----|
+| tutorial / howto | [runbook](runbook.md) — run anywhere (uv, Go, Docker) |
+| explanation | [design](design.md) — two roots, deduction, D17/D20/D18 |
+| howto | [picoclaw](picoclaw.md) — MCP agent profile |
+| howto | [reasoner](reasoner.md) — CPU bake-off (D18) |
+| reference | [PLAN.md](../PLAN.md) — decisions D1–D21 |
+
+Decisions the public face must name: **D3** SearXNG compose, **D6** Go service /
+Python write sidecar, **D14** `bin/{subject}/{method}.go`, **D15** Gitea origin,
+**D17** assertion gate (facts → info → web), **D18** pluggable reasoner.
 
 Search: `bin/brain/search.go "query"` (HTTP: `bin/brain/serve.go` —
 `/health` `/search` `/get` `/stats` `/audit` `/ingest`). `--hop` is
 not a walk; the flag errors until File/FROM_FILE edges exist.
 
-Published docs live here and mirror the project state.
+Work board: [Gitea issues](https://git.produktor.io/eSlider/2dph/issues).
+PRs and CI: GitHub [`eSlider/2dph`](https://github.com/eSlider/2dph).
+
+Published docs live here and match live commands.