Add "Hide in Cities" toggle to minimap icons dropdown

Reads zone ID from 0xB4E314 and suppresses NPC/GO tracking in capital
cities (SW, IF, Darn, Org, TB, UC, Alah'Thalas) when enabled. Castle
icon converted from WC3-style PNG via png2blp.

src/main.zig

@@ -96,6 +96,7 @@ fn registerLuaFunctions() void {
     if (build_opts.minimapicons and minimapicons.isActive()) {
         const lib = [_]lua.LuaReg{
             .{ .name = "SetObjectTypeBlip", .func = @intFromPtr(&minimapicons.luaSetObjectTypeBlip) },
+            .{ .name = "SetMinimapCityToggle", .func = @intFromPtr(&minimapicons.luaSetCityToggle) },
             .{ .name = null, .func = 0 },
         };
         lua.openlib(lua.getContext(), "WeirdUtils", &lib, 0);