Update the 1.6.4 entry to reflect the consolidated main: add the Lua 5.0
compatibility items (modulo->math.mod, Options {...} typo) and the native
objective POI sync, prestige cache reset, and quest completion cache fixes.
Fix the stale perf-refactor note that referenced the now-removed
phase2-lua50-sweep branch; remaining measured perf work is on
phase3-measured-perf and being cherry-picked one at a time. Mirror into the
HTML changelog and bump its version badge to v1.6.4.
Xurkon
a7de3eccb4
