D057 - The flat path table is real now, and it was built precisely because nothing here reads it

It was a placeholder: a list of paths under the right name. Every test passed, because a reader walks directory entries and never consults the table - so a wrong one fails only on the machine it was built for, which is the worst possible place to find out.

The format is a hash of each path mapped to its inode, sorted, with a bit marking directories. The hash is the familiar 31 * h + c over an upper-cased path, which is why two files differing only in case collide. Collisions need a second file this does not write, so has_collision answers the question before building and build refuses rather than emitting a table with an entry silently missing.