feat(watchers): add box stability watcher daemon, recovery guardrails, and CLI integration

- Add dedicated watchers/ project folder with box-stability-watcher.py supervisor
- Monitor host load, memory, swap saturation, and crash-looping services
- Implement tiered mitigations: yellow renicing, orange SIGSTOP pause with 60s grace, red shedding
- Distinguish user-launched agents (allowed on desktop default socket) from automated box workloads
- Wire first-class box stability CLI subcommand and top-line host status in fleet status
- Harden tmux.service with cgroup memory limits to prevent OS freeze and OOM avalanches
- Add 10-test unit test suite covering thresholds, safety whitelist, pause/resume, and isolation

systemd/box-stability-watcher.service

@@ -0,0 +1,16 @@
+[Unit]
+Description=NetVM Box & Host Stability Watcher Daemon
+After=network.target
+
+[Service]
+Type=simple
+ExecStart=/usr/bin/python3 /home/super/Projects/NetVM/watchers/box-stability-watcher.py --daemon
+Restart=always
+RestartSec=5
+MemoryMax=256M
+CPUQuota=50%
+StandardOutput=journal
+StandardError=journal
+
+[Install]
+WantedBy=default.target