Problem

CodexPanel rebuilds its entire entry list every time the panel is opened, even when no new discoveries have been made since the last open. For players with many discoveries, this creates unnecessary work.

Location

scripts/ui/codex_panel.gd

Suggested Fix

Track a dirty flag (set when new discoveries are made via signal) and only rebuild when dirty. Cache the built UI elements between opens.

Priority

Low — the codex is opened infrequently and rebuild cost is minimal for current content volume. Non-blocking.

Found during v0.7.0 performance review.