nightrider mode improvements, nice monitor, ready text 1x

- Nightrider: lines 1px wider (3px outline), engagement border hidden,
  planner lines hidden when disengaged, stay on onroad view in park
- Normal mode only: return to ready splash on park
- Ready text sprite at native 1x size
- Nice monitor: keeps claude processes at nice 19, runs every 30s

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

system/clearpilot/nice-monitor.sh

@@ -0,0 +1,19 @@
+#!/usr/bin/bash
+
+# Nice monitor — ensures claude processes run at lowest CPU priority.
+# Checks every 30 seconds and renices any claude process not already at nice 19.
+
+# Kill other instances of this script
+for pid in $(pgrep -f 'nice-monitor.sh' | grep -v $$); do
+  kill "$pid" 2>/dev/null
+done
+
+while true; do
+  for pid in $(pgrep -f 'claude' 2>/dev/null); do
+    cur=$(awk '{print $19}' /proc/$pid/stat 2>/dev/null)
+    if [ -n "$cur" ] && [ "$cur" != "19" ]; then
+      renice 19 -p "$pid" > /dev/null 2>&1
+    fi
+  done
+  sleep 30
+done