Add a video-guide recorder for the UI (Settings tabs, Event Manager tabs, Schedule panel)

CDP screencast -> ffmpeg -> MKV, driven against the same isolated server/browser pattern
the test suite already uses. Recorded three short clips demonstrating this session's tab
and schedule features; output goes to the gitignored video-guides/ folder rather than the
repo since these are sizeable binaries.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "rc-racecore",
-  "version": "1.17.2",
+  "version": "1.18.0",
   "private": true,
   "description": "RC RaceCore live timing and race control with AMMC ingest and SQLite persistence",
   "engines": {