http: add connect code into auth challenge detection

src/browser/HttpClient.zig

@@ -1261,7 +1261,9 @@ pub const Transfer = struct {
 
     fn detectAuthChallenge(transfer: *Transfer, conn: *const http.Connection) void {
         const status = conn.getResponseCode() catch return;
-        if (status != 401 and status != 407) {
+        const connect_status = conn.getConnectCode() catch return;
+
+        if (status != 401 and status != 407 and connect_status != 401 and connect_status != 407) {
             transfer._auth_challenge = null;
             return;
         }

src/network/http.zig

@@ -389,6 +389,15 @@ pub const Connection = struct {
         return url;
     }
 
+    pub fn getConnectCode(self: *const Connection) !u16 {
+        var status: c_long = undefined;
+        try libcurl.curl_easy_getinfo(self._easy, .connect_code, &status);
+        if (status < 0 or status > std.math.maxInt(u16)) {
+            return 0;
+        }
+        return @intCast(status);
+    }
+
     pub fn getResponseCode(self: *const Connection) !u16 {
         var status: c_long = undefined;
         try libcurl.curl_easy_getinfo(self._easy, .response_code, &status);

src/sys/libcurl.zig

@@ -178,6 +178,7 @@ pub const CurlInfo = enum(c.CURLINFO) {
     private = c.CURLINFO_PRIVATE,
     redirect_count = c.CURLINFO_REDIRECT_COUNT,
     response_code = c.CURLINFO_RESPONSE_CODE,
+    connect_code = c.CURLINFO_HTTP_CONNECTCODE,
 };
 
 pub const Error = error{
@@ -662,6 +663,7 @@ pub fn curl_easy_getinfo(easy: *Curl, comptime info: CurlInfo, out: anytype) Err
             break :blk c.curl_easy_getinfo(easy, inf, p);
         },
         .response_code,
+        .connect_code,
         .redirect_count,
         => blk: {
             const p: *c_long = out;