Fantastic news! Thank you.
Welcome to the forum. The bottom line is good news: you definitely are not at any risk of HIV or any other blood-borne infection from this sort of contact.
In the 40 years of the known worldwide HIV pandemic, not one case has ever been known to be acquired by the sort of contact you describe here. For example, people living in the same households as HIV infected persons (who are not sex or needle-sharing partners) never get infected despite years of sharing toilets, kitchens, towels, eating utensils, etc.
And by the way, the frequency of HIV is no higher in homeless persons than in the general population. If a homeless person is a gay man with multiple partners, a commercial sex worker, or an injection drug user, those factors would put them at risk -- but being homeless, in itself, is not a risk marker for HIV.
So my advice is to use common-sense hygiene (hand washing, an alcohol based disinfectant gel) to avoid colds, influenza, etc. But don't worry at all about HIV or blood-borne infections from handling phones, doorknobs, etc in your place of work.
I hope this has helped. Best wishes-- HHH, MD