UX: Backlog: Make story list thinner

Now that the story list is centered,
make it easier to scan from story state
(in progress, etc) to story owner by
making the column thinner.
Data: Basic integrity checks when moving stories

Put a band-aid over the integrity issue of moving
stories, to perhaps prevent things from breaking
more than they need to.

This code needs more test coverage and proper fixes.
Add page to fix simple integrity issues

We can detect if there are simple issues
with the story linked list, like if there
are next-id loops, and we can fix them
with a button push, now.

Suggested fixes should still be reviewed
before they're put in place, and really
we should fix the code so this page is
no longer necessary, but it is here for now.
Backlog: Link to 'fix' page when things break

When we detect a broken backlog, show the user
a message and direct them to our diagnostic page
to see if the fix is a simple one.