Preview: isRunnerDev einheitlich (Reconcile, Dev-Start), 137-Fehlertext

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

test/previewAdmin.test.js

@@ -192,6 +192,16 @@ test('Rebuild und Dev start/stop', async () => {
   assert.ok(rs.calls.some((c) => c.url === '/dev/web/stop'))
 })
 
+test('dev/start: oeffentliche Seite ausserhalb Modus dev => 409', async () => {
+  const { createDocument } = await import('../server/services/appwriteAdmin.js')
+  await createDocument('websiteProjects', { projectName: 'Pub', repoFullName: 'JUSN/pub', subdomain: 'pub', previewBranch: 'main', previewBuiltSha: SHA, previewState: 'online', previewDetected: 'static', isPublic: true, previewMode: 'auto' }, 'ppub')
+  rs.calls = []
+  const r = await call('POST', '/ppub/preview/dev/start')
+  assert.equal(r.status, 409)
+  assert.deepEqual(await r.json(), { error: 'Öffentliche Seite: Dev-Server nur im Modus Dev-Server' })
+  assert.equal(rs.calls.filter((c) => c.url.startsWith('/dev/')).length, 0)
+})
+
 test('Schalter aus: Schreib-Routen 409, GET geht', async () => {
   cfg.previewRunner.enabled = false
   for (const [m, p, b] of [['PATCH', '/pw/preview', { mode: 'auto' }], ['PUT', '/pw/preview/env', { set: {} }],