Add `poc-memory admin bulk-rename FROM TO [--apply]` for bulk key
character replacement. Uses rename_node() per key for proper capnp
log persistence. Collision detection, progress reporting, auto-fsck.
Applied: renamed 13,042 keys from # to - separator. This fixes the
Claude Bash tool's inability to pass # in command arguments (the
model confabulates that quoting doesn't work and gives up).
7 collision pairs resolved by deleting the # version before rename.
209 orphan edges pruned by fsck.
Co-Authored-By: Kent Overstreet <kent.overstreet@linux.dev>
f8221286da