Slice 1: surface system + WS transport + composition root

Pure-core feature libraries assembled at the composition root:
- core/protocol: pure reducer over surface catalog/spec/error messages
- features/surface-host: generic field-kind interpreter (toggle/progress/
  selector/stat/button) + pure plan logic; no surface-id special-casing
- adapters/ws: injected WebSocket client (effects at the edge)
- app: composition root store (Svelte 5 runes over the pure reducer),
  host-relative surface WS URL resolution (resolveWsUrl), root App.svelte

Verified green: svelte-check 0/0, vitest 84 passed, biome clean, vite build ok.

1 files changed, 10 insertions, 0 deletions

diff --git a/src/features/surface-host/ui/Stat.svelte b/src/features/surface-host/ui/Stat.svelte
new file mode 100644
index 0000000..e184dab
--- /dev/null
+++ b/src/features/surface-host/ui/Stat.svelte
@@ -0,0 +1,10 @@
+<script lang="ts">
+	import type { StatFieldView } from "../logic/types";
+
+	let { field }: { field: StatFieldView } = $props();
+</script>
+
+<dl>
+	<dt>{field.label}</dt>
+	<dd>{field.value}</dd>
+</dl>