Add jukebox_maker web app v1.0

Go web application for filling USB drives with media files.
Runs in Docker on Unraid with /media, /mnt/usb, /config volumes.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitignore

@@ -25,3 +25,9 @@ go.work.sum
 # env file
 .env
 
+# Build output
+/jukebox
+
+# Temp copy files
+*.juketmp
+