Thanks for the detailed report — you caught two real bugs and surfaced a third.
The freeze was a missing role definition (fisher was in the game but not in
the daily production table — it would crash the day-tick the first time a
fisher started working, which fits your "Year 1 Day 8" timing). The
ReferenceError every 30 seconds was the auto-save trying to look up a
variable that wasn't in scope.
Bigger fix: the game loop now catches errors so a single bad tick won't
freeze the whole game ever again — it logs the error and keeps running.
All three fixed in 5.39, just pushed. Hard-refresh and your save should
load right where you left off. Sorry you had to be the first one to hit
this — let me know if you find anything else.
— Adrian