feat: D.6 first-run wizard — detect, start, link, group, gek-init, pair

Desktop client guides new users through the full onboarding sequence
without a terminal: detect local node → start daemon (systemd with
direct-start fallback for dev) → link node key to hub → create group →
attach directories → gek-init → operator pair.

- node:detect returns configured field to distinguish missing vs stopped
- node:start tries systemctl first, checks is-active, falls back to
  spawning the binary directly when the unit crashes (dev mode)
- probeNode() extracts the shared config→token→fetch pattern
- SetupWelcome on empty HomePage links to /create-group
- CreateGroupWizard step 0 handles node detection and start
- platform.js exposes node.installed() and node.start()
- 12 setup.* i18n keys added to all 10 locales
- Integration test for node:start fallback logic

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/packages/meshbay-hub/src/meshbay_hub/static/platform.js b/packages/meshbay-hub/src/meshbay_hub/static/platform.js
index d400b4e..eeffd49 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/platform.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/platform.js
@@ -224,6 +224,13 @@ export const node = {
   async detect() {
     return bridge && bridge.node ? bridge.node.detect() : { detected: false };
   },
+  async installed() {
+    return bridge && bridge.node ? bridge.node.installed() : { installed: false };
+  },
+  async start() {
+    if (!bridge || !bridge.node) throw new Error('Node bridge not available');
+    return bridge.node.start();
+  },
   async call(method, path, body) {
     if (!bridge || !bridge.node) throw new Error('Node bridge not available');
     return bridge.node.call(method, path, body);