API accessibility with DNS failover. Major cleanup
- Removed experimental DNS multi-IP failover from CLI (URL-level failover only)
- Fixed Windows CLI build: 3-URL failover was missing (CMake BOOL bug with URLs)
- Fixed Windows CLI CMakeLists.txt generator expression for URL defines
- All platforms verified: 3 API URLs + beta.p4pn.net site URL baked in
- Build scripts output installers to Release/ (deploy stages to Site/download/)