Add runbook for recovering wedged units and new scripts for device management

- Created a comprehensive runbook (`wedged_unit_recovery.md`) detailing the recovery process for units stuck in a call-home loop, including symptoms, recovery steps, and explanations of the failure mode.
- Added `blind_stop.sh` script to send stop-monitoring commands in a tight loop for unresponsive devices.
- Introduced `rescue_device.sh` script to disable Auto Call Home and erase events from a busy device.
- Implemented `slow_drip.sh` script to send stop-monitoring frames at a slow rate to prevent UART overrun.
- Developed `spam_stop.sh` script to rapidly send stop-monitoring commands to a device.
- Created `watch_unit.sh` script for passive monitoring of device reachability, logging results over time.

scripts/spam_stop.sh

@@ -0,0 +1,48 @@
+#!/usr/bin/env bash
+# Hammer a device with blind stop-monitoring sessions as fast as possible.
+# Single HTTP call kicks off the burst inside SFM (no per-attempt HTTP
+# overhead).  Default: 10 seconds, ~500 ms per attempt = ~20 attempts/sec.
+#
+# Usage:
+#   ./spam_stop.sh <host> [tcp_port] [duration_s]
+#
+# Examples:
+#   ./spam_stop.sh 166.246.130.1                  # 10s burst
+#   ./spam_stop.sh 166.246.130.1 9034 30          # 30s burst
+#   DURATION=60 CONNECT_TIMEOUT=0.2 ./spam_stop.sh 166.246.130.1
+#
+# Env:
+#   SFM_BASE_URL     Default: http://localhost:8200 (SFM direct).
+#                    Set to http://localhost:8001/api/sfm to route through
+#                    Terra-View's proxy — but note the proxy has a 60s
+#                    timeout, so long bursts need direct mode.
+#   DURATION         Default: 10 (seconds; arg 3 overrides)
+#   CONNECT_TIMEOUT  Default: 0.5 (seconds)
+#   REPEAT           Default: 3   (stop frames per TCP session)
+
+set -u
+
+host="${1:-}"
+tcp_port="${2:-9034}"
+duration="${3:-${DURATION:-10}}"
+
+if [[ -z "$host" ]]; then
+  echo "usage: $0 <host> [tcp_port] [duration_s]" >&2
+  exit 2
+fi
+
+base="${SFM_BASE_URL:-http://localhost:8200}"
+connect_timeout="${CONNECT_TIMEOUT:-0.5}"
+repeat="${REPEAT:-3}"
+
+url="${base}/device/stop_monitoring_spam?host=${host}&tcp_port=${tcp_port}&duration_s=${duration}&connect_timeout=${connect_timeout}&repeat=${repeat}"
+
+echo "spam_stop: target ${host}:${tcp_port}  duration=${duration}s  connect_timeout=${connect_timeout}s  repeat=${repeat}"
+echo "spam_stop: POST ${url}"
+echo
+
+# Give curl enough slack to wait out the duration plus a buffer
+max_time=$(awk -v d="$duration" 'BEGIN { printf "%d", d + 10 }')
+
+curl -sS --max-time "$max_time" -X POST "$url"
+echo