Home mosaic, multi-select delete, offline banner and loading states

- Home puts the dashboards beside the flows: two equal-height columns,
  capped and scrollable, most recently worked on first. Each tile is a
  schematic footprint built from the stored widget placements.
- Flows and dashboards can be picked by long press or ctrl-click; the
  create button becomes a trash and one dialog covers the batch.
- The offline banner is drawn on the body so it centres on the viewport,
  and the live socket now releases the offline latch a stray 503 set.
- A boot spinner before React's first commit, a router pending screen for
  code-split pages, and skeletons where an empty list used to flash.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018tULRZJUkZsw7rMJ3h4xvu

docs/interface/index.md

@@ -26,7 +26,7 @@ phone the sidebar collapses to a sheet.
 
 ## Home
 
-The one screen you leave open. Three things share it.
+The one screen you leave open. Four things share it.
 
 ### The brain graph
 
@@ -38,6 +38,18 @@ its label showing so you can see which one it is without hovering.
 
 Each flow also has a switch beside it in the list, which starts and stops it.
 
+### Flows and dashboards
+
+Two columns under the graph, exactly as tall as each other, most recently
+worked on first. The flows column is the list with the switches; the dashboards
+column is a mosaic, each tile a schematic of that dashboard's layout — blocks
+where its widgets sit, shaded by what kind of widget each one is. Neither
+column grows past about six rows: past that it scrolls in place rather than
+pushing the health block down the page.
+
+The tiles are a footprint, not a live view. They show you which dashboard is
+which at a glance; the readings are on the dashboard itself.
+
 ### Health
 
 Always answers, degraded or not. The tiles cover:
@@ -70,6 +82,13 @@ creates, and offers **Publish all changes** when several flows have drafts.
 
 Opening one takes you to [the flow editor](flow-editor.md).
 
+### Deleting several at once
+
+Press and hold a card — or ctrl-click it — to pick it, then tap the rest. While
+anything is picked, **New flow** in the toolbar becomes a trash button, and it
+asks once before deleting the lot. Unpicking the last one puts the list back;
+so does Escape. The Dashboards screen works the same way.
+
 ## Everything else
 
 - [The flow editor](flow-editor.md) — the canvas, the code editor, running and