fix: keep vite UI reachable over Tailscale (PM2 launch + host binding)

- PM2 now launches vite from the repo-root bin (absolute path) with
  interpreter: node, fixing an ERR_MODULE_NOT_FOUND crash loop that took
  port 6373 down whenever npm hoisted vite out of the client workspace.
- vite binds 0.0.0.0 and de-duplicates the allowedHosts key (`.ts.net`),
  so the UI is reachable across the tailnet over HTTP, or HTTPS when
  fronted by `tailscale serve`.

Author: atomantic

.changelog/NEXT.md

@@ -12,7 +12,8 @@
 
 - Provider comparison cards no longer emit an invalid nested-`<button>` HTML warning under React 19 (the card header is now a `role="button"` element, keeping click and keyboard toggling).
 - SQLite driver is now loaded lazily so the server can start and serve JSON-backed data even when the native binding is unavailable.
-- Dev server accepts requests from any host (`allowedHosts: true`) so the UI is reachable via Tailscale hostnames.
+- Dev server binds all interfaces and accepts Tailscale `*.ts.net` hostnames, so the UI is reachable across the tailnet (over plain HTTP, or HTTPS when fronted by `tailscale serve`).
+- PM2 launches the vite UI via the repo-root bin path with an explicit node interpreter, fixing a crash loop (`ERR_MODULE_NOT_FOUND`) that left port 6373 down when npm hoisted vite out of the client workspace.
 
 ## Added
 

client/vite.config.ts

@@ -5,11 +5,12 @@ import tailwindcss from '@tailwindcss/vite';
 export default defineConfig({
   plugins: [react(), tailwindcss()],
   server: {
-    allowedHosts: true,
+    host: '0.0.0.0',
     port: 6373,
-    // Allow access over Tailscale MagicDNS (https://<node>.<tailnet>.ts.net/)
-    // fronted by `tailscale serve`. A leading dot matches the domain and all
-    // subdomains, so every node name in the tailnet is accepted.
+    // Allow access over Tailscale MagicDNS (http://<node>.<tailnet>.ts.net:6373/,
+    // or https://<node>.<tailnet>.ts.net/ when fronted by `tailscale serve`).
+    // A leading dot matches the domain and all subdomains, so every node name
+    // in the tailnet is accepted.
     allowedHosts: ['.ts.net'],
     proxy: {
       '/api': {

ecosystem.config.cjs

@@ -30,8 +30,13 @@ module.exports = {
     },
     {
       name: 'sparsetree-ui',
-      script: 'node_modules/.bin/vite',
+      // vite is hoisted to the repo-root node_modules in this npm workspace, so
+      // reference the root bin via an absolute path (the client-local .bin/vite
+      // may not exist). interpreter: 'node' so pm2 execs the bin instead of
+      // trying to import() it as an ESM module.
+      script: `${__dirname}/node_modules/.bin/vite`,
       cwd: `${__dirname}/client`,
+      interpreter: 'node',
       args: `--host 0.0.0.0 --port ${PORTS.UI}`,
       env: {
         NODE_ENV: 'development',