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, 23 insertions, 0 deletions

diff --git a/vite.config.ts b/vite.config.ts
new file mode 100644
index 0000000..fab62a0
--- /dev/null
+++ b/vite.config.ts
@@ -0,0 +1,23 @@
+import { svelte } from "@sveltejs/vite-plugin-svelte";
+import { defineConfig } from "vitest/config";
+
+// Dev server on the reserved FRONTEND_PORT (24204). Vitest config lives here too
+// (jsdom + globals) so component tests run without extra config.
+export default defineConfig({
+	plugins: [svelte()],
+	// Bind all interfaces + accept any Host header so the dev server is reachable over a LAN /
+	// Tailscale. Safe for LOCAL-NETWORK-ONLY use (NOT internet-exposed): `allowedHosts: true`
+	// disables Vite's DNS-rebinding host check. (The WS URL still runs in the browser — set
+	// VITE_WS_URL to the backend's reachable host when browsing from another device.)
+	server: { port: 24204, host: true, allowedHosts: true },
+	test: {
+		environment: "jsdom",
+		globals: true,
+		setupFiles: ["./vitest-setup.ts"],
+		// Svelte 5's exports map resolves `svelte` → server build under the default
+		// condition; force the browser build so component tests can mount().
+		resolve: {
+			conditions: ["browser"],
+		},
+	},
+});