0.10.0: Archify Sync, optional live collaboration on a model

Several people edit one model at once through a server you run yourself
(archify-vscode-ext-sync); the files stay ordinary files on each disk.
Sign-in through the browser, offline-first with later merge, teammates'
cursors in the Source view and text editors, and a Shared section on the
model page with people, versions, Compare and Restore.

Without a server nothing changes: the sync code is a separate bundle that
loads only when a model is shared, after a sign-in, or when a sync command
or invite link is used.

esbuild.mjs

@@ -51,6 +51,14 @@ if (tests) {
       outfile: 'dist/extension.js',
       external: ['vscode'],
     }),
+    // Archify Sync, loaded only when a model is shared (src/sync/loader.ts).
+    // ws's native speed-ups are optional and not shipped.
+    esbuild.context({
+      ...common,
+      entryPoints: ['src/sync/index.ts'],
+      outfile: 'dist/sync.js',
+      external: ['vscode', 'bufferutil', 'utf-8-validate'],
+    }),
     // Runs inside the Archify page in the webview; three.js is bundled in.
     esbuild.context({
       ...common,