HttpClient using libcurl, Unix Sockets for HTTP. HTTPS support (#770)

The main goal of this change is to eliminate the cpr back-end altogether and replace it with the curl implementation. I would expect to drop cpr as soon as we feel happy with the libcurl back-end. That would leave us with a direct dependency on libcurl only, and cpr can be eliminated as a dependency.

### HttpClient Backend Overhaul
- Implemented a new **libcurl-based HttpClient** backend (`httpclientcurl.cpp`, ~2000 lines)
  as an alternative to the cpr-based one
- Made HttpClient backend **configurable at runtime** via constructor arguments
  and `-httpclient=...` CLI option (for zen, zenserver, and tests)
- Extended HttpClient test suite to cover multipart/content-range scenarios

### Unix Domain Socket Support
- Added Unix domain socket support to **httpasio** (server side)
- Added Unix domain socket support to **HttpClient**
- Added Unix domain socket support to **HttpWsClient** (WebSocket client)
- Templatized `HttpServerConnectionT<SocketType>` and `WsAsioConnectionT<SocketType>`
  to handle TCP, Unix, and SSL sockets uniformly via `if constexpr` dispatch

### HTTPS Support
- Added **preliminary HTTPS support to httpasio** (for Mac/Linux via OpenSSL)
- Added **basic HTTPS support for http.sys** (Windows)
- Implemented HTTPS test for httpasio
- Split `InitializeServer` into smaller sub-functions for http.sys

### Other Notable Changes
- Improved **zenhttp-test stability** with dynamic port allocation
- Enhanced port retry logic in http.sys (handles ERROR_ACCESS_DENIED)
- Fatal signal/exception handlers for backtrace generation in tests
- Added `zen bench http` subcommand to exercise network + HTTP client/server communication stack

1 files changed, 4 insertions, 3 deletions

diff --git a/src/zenremotestore/builds/jupiterbuildstorage.cpp b/src/zenremotestore/builds/jupiterbuildstorage.cpp
index 8e16da1a9..c3f7b9e71 100644
--- a/src/zenremotestore/builds/jupiterbuildstorage.cpp
+++ b/src/zenremotestore/builds/jupiterbuildstorage.cpp
@@ -23,9 +23,10 @@ using namespace std::literals;
 namespace {
 	[[noreturn]] void ThrowFromJupiterResult(const JupiterResult& Result, std::string_view Prefix)
 	{
-		int				 Error = Result.ErrorCode < (int)HttpResponseCode::Continue ? Result.ErrorCode : 0;
-		HttpResponseCode Status =
-			Result.ErrorCode >= int(HttpResponseCode::Continue) ? HttpResponseCode(Result.ErrorCode) : HttpResponseCode::ImATeapot;
+		HttpClientErrorCode Error  = Result.ErrorCode < static_cast<int>(HttpResponseCode::Continue) ? HttpClientErrorCode(Result.ErrorCode)
+																									 : HttpClientErrorCode::kOK;
+		HttpResponseCode	Status = Result.ErrorCode >= static_cast<int>(HttpResponseCode::Continue) ? HttpResponseCode(Result.ErrorCode)
+																									  : HttpResponseCode::ImATeapot;
 		throw HttpClientError(fmt::format("{}: {} ({})", Prefix, Result.Reason, Result.ErrorCode), Error, Status);
 	}
 }  // namespace