That's why, then - if you did a make && make install you'll only get the base config files, but you'll miss the package configuration step that would have asked you for the superuser details.
I would recommend uninstalling and building a package, and then installing that with dpkg -i - it's much safer (trust me, I've been there).
If you want to hack it manually...
What you have is the config that's been created when you run tvheadend with -C - in effect, you're running it as yourself but without access control, hence the config is in your home directory.
If you run it as a daemon, you need to specify the user (-u hts) and group (-g video) under which the forked (-f) process should run. The config files will then be under that user... you may have created them under /home/root or similar if you've just used -f, or it may have defaulted to hts, I don't know without testing.
The accesscontrol rules apply to the web interface. You should be able to see each rule defines a different user and different permissions.
You should also have a file - superuser - in the /home/USER/.hts/tvheadend directory (USER is whichever user you're running it as) that defines the master user.
{
"username": "USERNAME,
"password": "PASSWORD"
}
