Victorian Idle City Builder

* Improved overall game performance. * Lowered idle difficulty by 5% for smoother long-session progression. * Increased merchant inventory from 1M to 100M. * Referral notifications now stay visible longer so they're easier to notice. * Added a tooltip to the incident minigame clarifying that it can keep running in the background. * Fixed puzzle validation edge case when identical tiles were involved. * Fixed an issue where a war could sometimes start while an ad was being displayed. * Protected shipyards from incidents so they can no longer be accidentally destroyed. * Fixed a rare case where resource deltas could flip between positive and negative every second.