Address code review feedback for HTTP client and server

Based on code review feedback:

Client improvements:
- Remove redundant capacity check in http_client_get_builder
  (already verified num_conns < capacity)
- Fix generation counter - no longer reset to zero when allocating
  connections, only incremented on request send
- Add HTTP_Method parameter to http_request_builder_url instead
  of hardcoding GET method
- Free connection resources when http_request_builder_send fails
  (invalid host mode or socket_connect failure)

Server bug fix:
- Fix ready queue indexing in http_server_next_request
  Changed: &server->conns[server->ready_head]
  To: &server->conns[server->ready[server->ready_head]]
  This bug would have caused incorrect connection retrieval

All changes maintain consistency with the codebase style and
improve robustness of error handling.

src/parse.c

@@ -435,7 +435,7 @@ static int is_scheme_body(char c)
 // Note: percent-encoded characters (%XX) are not currently validated
 static int is_userinfo(char c)
 {
-	return is_unreserved(c) || is_sub_delim(c) || c == ':' || c == '%';
+	return is_unreserved(c) || is_sub_delim(c) || c == ':';
 }
 
 // authority = [ userinfo "@" ] host [ ":" port ]