The mod manager's ModUpdate.parseRelease only accepts tags matching
^(\d+\.\d+\.\d+)$ and silently drops v-prefixed tags, so the auto-created
v1.8.4 release was invisible in-game. Drop the "v" prefix from the generated
tag and from the previous-tag lookup so releases are picked up correctly.

Co-Authored-By: Hermes Agent <noreply@nousresearch.com>