fix: BUG-33 CPU threshold, TASK-27 tab icons, TASK-36 iframe errors

- BUG-33: CPU load alert threshold increased from 2x to 4x core count
  (8→16 on 4-core machine) to reduce false alerts during container ops
- TASK-27: Launch buttons for new-tab apps now show external link icon
  (BTCPay, Grafana, PhotoPrism, Portainer, OnlyOffice, etc.)
- TASK-36: Iframe error screen now distinguishes between X-Frame-Options
  blocked vs container not reachable, with appropriate messaging

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

neode-ui/DEV-SCRIPTS.md

@@ -107,20 +107,22 @@ tail -f /tmp/neode-dev.log
 ## Features
 
 ### Mock Backend
-- **Docker Optional** - Apps run for real if Docker is available, otherwise simulated
-- **Auto-Detection** - Automatically detects Docker daemon and adapts
-- **Fixed Port Allocation** - atob:8102, k484:8103, amin:8104
-- **WebSocket Support** - Real-time updates
-- **Pre-loaded Apps** - Bitcoin and Lightning already "installed"
+- **Docker Optional** - Apps run for real if Docker/Podman is available, otherwise simulated
+- **Auto-Detection** - Automatically detects container runtime and adapts
+- **WebSocket Support** - Real-time state updates via JSON patches
+- **Pre-loaded Apps** - 8 apps always visible in My Apps
 
-📖 **See [DOCKER-APPS.md](./DOCKER-APPS.md) for running real Docker containers**
+### Pre-installed Apps (always running in mock mode)
+- `bitcoin` - Bitcoin Core (port 8332)
+- `lnd` - Lightning Network Daemon (port 8080)
+- `electrs` - Electrum Server in Rust (port 50001)
+- `mempool` - Blockchain explorer (port 4080)
+- `filebrowser` - Web file manager (port 8083)
+- `lorabell` - LoRa doorbell (no UI port)
+- `thunderhub` - Lightning node management (port 3010)
+- `fedimint` - Federated Bitcoin mint (port 8175)
 
-### Available Test Apps
-- `atob` - A to B Bitcoin (simulated)
-- `k484` - K484 POS/Admin (simulated)
-- `amin` - Admin interface (simulated)
-
-All installations are simulated - they don't actually download or run Docker containers.
+Additional apps can be installed from the Marketplace (30+ available).
 
 ---