reference: commit the real-boot frame evidence (33MB) with a NOTES.md; gitignore the 201MB source recording

.gitignore

@@ -36,3 +36,9 @@ tools/ghidra-headless-mcp/
 
 # Generated harness logs
 harness/mame/board-*.log
+harness/mame/gui.log
+
+# Large media: the source recording stays out of git (a YouTube download,
+# trivially re-obtainable).  The derived frames and contact sheets ARE committed,
+# as evidence — see reference/vt1200-boot-video/NOTES.md for the regeneration recipe.
+video/