feat(ui): 2.0.0-alpha.12 — editable Sacred Valley layout

Edit-layout mode: per-card resize (S/M/L), show/hide with a hidden-cards tray,
drag-to-reorder via a dedicated grip handle, and reset-to-default. Persists via
the existing /api/dashboard/layout (order/sizes/hidden) — no backend change.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

CHANGELOG.md

@@ -3,6 +3,10 @@
 All notable changes to Void 2.0 are documented here.
 Format: [Keep a Changelog](https://keepachangelog.com).
 
+## 2.0.0-alpha.12 — Editable Sacred Valley layout
+- "Edit layout" mode on the dashboard: per-card **resize** (S/M/L column span), **show/hide** (with a hidden-cards tray to re-add), clearer **drag-to-reorder** via a dedicated grip handle, and a **Reset** to defaults.
+- All changes persist through the existing `/api/dashboard/layout` (order/sizes/hidden) — no backend changes.
+
 ## 2.0.0-alpha.11 — DB-backed service registry + LAN auto-discovery
 - The health-band registry is now in Postgres (`monitored_services`, migration 015) instead of the hand-edited `config/services.json` — which becomes a one-time boot seed (auto-populated if the table is empty).
 - Owner CRUD over the registry: `POST/PATCH/DELETE /api/health/services` (add/edit/enable/disable/remove); `GET /api/health/services` is now DB-backed.