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, 13 insertions, 0 deletions

diff --git a/src/features/surface-host/ui/Progress.svelte b/src/features/surface-host/ui/Progress.svelte
new file mode 100644
index 0000000..cba9e0f
--- /dev/null
+++ b/src/features/surface-host/ui/Progress.svelte
@@ -0,0 +1,13 @@
+<script lang="ts">
+	import type { ProgressFieldView } from "../logic/types";
+
+	let { field }: { field: ProgressFieldView } = $props();
+
+	const percent = $derived(Math.round(field.value * 100));
+</script>
+
+<div>
+	<span>{field.label}</span>
+	<progress max="100" value={percent}>{percent}%</progress>
+	<span>{percent}%</span>
+</div>