webui: make the committed bundle reproducible

webui/native/package.json

@@ -1,7 +1,7 @@
 {
   "name": "audiocpp-native-webui",
   "private": true,
-  "version": "0.1.0",
+  "version": "0.8.1",
   "type": "module",
   "scripts": {
     "dev": "vite dev",

webui/native/svelte.config.js

@@ -1,5 +1,29 @@
+import { readFileSync } from 'node:fs';
+
 import adapter from '@sveltejs/adapter-static';
 
+// SvelteKit defaults kit.version.name to Date.now() and derives the
+// __sveltekit_<id> global it embeds in dist/index.html from it, so two builds
+// of identical source differ. dist/index.html is committed -- it is embedded
+// into the server binary at configure time, which is what lets the project
+// build a working server without a JavaScript toolchain -- so any two branches
+// that rebuild the web UI conflict in it whether or not their source changes
+// overlap.
+//
+// Naming the version after the UI package makes the bundle a pure function of
+// the source tree. Keep webui/native/package.json's version in step with the
+// release it ships in; nothing derives it automatically, because audio.cpp's
+// own version is tag-driven (AUDIOCPP_VERSION is passed at configure time and
+// is not committed anywhere in the tree).
+//
+// Note that this is an identifier, not a live update channel: the app never
+// imports SvelteKit's `updated` store, version.pollInterval is left at its
+// default of 0, and the single-file bundle ships no _app/version.json for the
+// client to poll. A stale version here costs nothing but a stale label.
+const { version } = JSON.parse(
+  readFileSync(new URL('./package.json', import.meta.url), 'utf8')
+);
+
 /** @type {import('@sveltejs/kit').Config} */
 const config = {
   kit: {
@@ -17,6 +41,9 @@ const config = {
     },
     paths: {
       relative: true
+    },
+    version: {
+      name: version
     }
   }
 };