Close REUSE-WP-0011 follow-ups: archive, docs, A4 promotion

- Archive workplan to workplans/archived/260615-REUSE-WP-0011-*.md
- Document browser landing page routing in FederationHubAPI and deploy docs
- Promote capability.registry.register to A4 (hosted hub API evidence)
- Update SCOPE finished workplan list

specs/FederationHubAPI.md

@@ -13,7 +13,21 @@ The federation hub is a hosted coordination service that records which
 repositories publish capability indexes and serves a composed federated index
 for agent discovery. It does **not** store capability entry Markdown bodies.
 
-Companion deployment workplan: `railiance-apps` **RAILIANCE-WP-0007**.
+Companion deployment workplans: `railiance-apps` **RAILIANCE-WP-0007** (Helm
+release), **RAILIANCE-WP-0008** (browser landing page).
+
+### Browser vs API routing
+
+Production ingress (owned by `railiance-apps`) splits paths:
+
+| Path | Handler |
+|---|---|
+| `GET /` (HTTPS) | Static landing page (`reuse-surface-landing`) — humans only |
+| `GET /health`, `GET /v1/*` | Hub API (`reuse-surface` service) |
+
+The landing page does not implement registration or federation; clients and
+agents should use `/health` and `/v1/*` only. See
+`railiance-apps/docs/reuse-surface-on-railiance01.md`.
 
 ---
 
@@ -261,4 +275,6 @@ Run locally: `reuse-surface serve`. Global client flags: `--base-url`, env
 - Secret: `reuse-surface-env` with `REUSE_SURFACE_TOKEN`
 - Probe path: `/health`
 - Persistence: PVC at `/data` (SQLite + fetch cache)
-- Helm release: `railiance-apps` RAILIANCE-WP-0007
+- Helm release: `railiance-apps` RAILIANCE-WP-0007
+- Landing page at `/`: `railiance-apps` RAILIANCE-WP-0008 (disable via
+  `landing.enabled: false` in Helm values)