I checked the gh actions prior to #119, the logs say our builds contained warnings (see [1]).
To prevent introducing additional warnings in the future, I propose to enable compile warning as error.

[1] https://github.com/apache/iceberg-cpp/actions/runs/15406978076/job/43351431102?pr=113#step:3:192

Oops, it found a few more warnings on windows platform. Do you think it’s worth addressing these? @wgtmac @lidavidm

https://github.com/apache/iceberg-cpp/actions/runs/15777841435/job/44476206590?pr=125#step:4:589

MSVC tends to be oddly finicky but it's probably worth fixing those

Let's move this forward, thanks @zhjwpku for working on this, and thanks @lidavidm, @wgtmac and @mapleFU for the review!