Phase 999: add multi-guild export UI journey stub (v0.8.966)

Non-breaking headless journey stub for mesh stability UI multi-guild export
keys + embed snapshot verification. No platform API or behavior changes.

Co-authored-by: Cursor <[email protected]>

headless.js

@@ -1847,6 +1847,30 @@ class HeadlessSession {
     }
   }
 
+  /** Journey stub: mesh stability UI multi-guild export keys + embed snapshot (Phase 999). */
+  async runMeshStabilityUiMultiGuildExportJourney (guildId) {
+    if (!this.platform) throw new Error('headless not started')
+    const gid = guildId || this.platform.guild?.guild?.id
+    if (!gid) throw new Error('no guild')
+    const path = require('bare-path')
+    const {
+      listMeshStabilityUiMultiGuildExportFieldKeys,
+      buildMeshStabilityMultiGuildExportSnapshot
+    } = require('pearcord-platform/mesh-stability-ui-multi-guild-export-keys')
+    const uiPath = path.join(__dirname, '..', '..', 'apps', 'pearcord', 'ui', 'mesh-stability-ui-multi-guild-export.js')
+    const { buildMeshStabilityMultiGuildExportEmbedHtml } = await import(uiPath)
+    const view = await this.refreshView()
+    const fields = listMeshStabilityUiMultiGuildExportFieldKeys()
+    const snapshot = buildMeshStabilityMultiGuildExportSnapshot({
+      ...view,
+      guilds: [{ id: gid }, { id: 'guild-stub-b' }]
+    })
+    const embedHtml = buildMeshStabilityMultiGuildExportEmbedHtml({
+      guilds: [{ id: gid }, { id: 'guild-stub-b' }]
+    })
+    return { guildId: gid, fields, snapshot, embedHtml, view }
+  }
+
   /** Journey stub: mesh stability UI member page keys + embed snapshot (Phase 998). */
   async runMeshStabilityUiMemberPageJourney (guildId) {
     if (!this.platform) throw new Error('headless not started')