fix(watchdogs): Tailscale false positive + system watchdog banner

network_watchdog: Tailscale JSON uses "BackendState": "Running" (with space)
but grep pattern matched "BackendState":"Running" (no space) — always failed.
Switched to grep -qE with \s* to handle both forms.

system_watchdog: add echo banner at run start so its output is visually
separated from docker_watchdog in orchestrator logs. Previously appeared
as a continuation of the docker section since docker_watchdog has a banner
but system_watchdog did not.

Watchdogs/System/network_watchdog.sh

@@ -173,7 +173,7 @@ if [[ "$SHOW_STATUS" == true ]]; then
     fi
 
     if [[ "${NETWORK_WATCHDOG_CHECK_TAILSCALE:-true}" == "true" ]] && command -v tailscale >/dev/null 2>&1; then
-        if tailscale status --json 2>/dev/null | grep -q '"BackendState":"Running"'; then
+        if tailscale status --json 2>/dev/null | grep -qE '"BackendState":\s*"Running"'; then
             echo "  $ICON_SUCCESS Tailscale:  running"
         else
             echo "  $ICON_ERROR  Tailscale:  NOT running"
@@ -254,7 +254,7 @@ fi
 if [[ "${NETWORK_WATCHDOG_CHECK_TAILSCALE:-true}" == "true" ]]; then
     if ! command -v tailscale >/dev/null 2>&1; then
         log "Tailscale not installed — skipping"
-    elif tailscale status --json 2>/dev/null | grep -q '"BackendState":"Running"'; then
+    elif tailscale status --json 2>/dev/null | grep -qE '"BackendState":\s*"Running"'; then
         log "$ICON_SUCCESS Tailscale running"
     else
         warn "$ICON_ERROR Tailscale not in Running state"

Watchdogs/system_watchdog.sh

@@ -84,6 +84,8 @@ fi
 # ==============================================================================================
 # ━━━ Run Sequence ━━━
 # ==============================================================================================
+echo "━━━ $ICON_SHIELD System Watchdog — $(date '+%Y-%m-%d %H:%M:%S') ━━━"
+
 START=$(date +%s)
 PASSED=()
 FAILED=()