feat(FN-1821): add settings and auth sync API routes for mesh nodes

- Add GET /api/nodes/:id/settings endpoint to fetch remote node settings
- Add POST /api/nodes/:id/settings/push to push local settings to a remote node
- Add POST /api/nodes/:id/settings/pull to pull settings from a remote node
- Add GET /api/nodes/:id/settings/sync-status for sync diff summary
- Add POST /api/nodes/:id/auth/sync to sync model auth credentials
- Add POST /api/settings/sync-receive inbound settings endpoint
- Add POST /api/settings/auth-receive inbound auth endpoint
- Add GET /api/settings/auth-export to export local auth credentials
- Add comprehensive route tests for all sync endpoints
- Update AGENTS.md with Node Settings Sync API reference

pnpm-lock.yaml

@@ -142,6 +142,9 @@ importers:
       '@fusion/engine':
         specifier: workspace:*
         version: link:../engine
+      '@mariozechner/pi-coding-agent':
+        specifier: ^0.62.0
+        version: 0.62.0(@modelcontextprotocol/sdk@1.28.0(zod@4.3.6))(ws@8.20.0)(zod@4.3.6)
       '@types/multer':
         specifier: ^2.1.0
         version: 2.1.0