Add bokeh background blur — AI Bokeh & Depth filter

The plain-language version of the entire bokeh category: blur my background, keep me sharp. This filter applies professional depth-of-field without any stylistic agenda — no hearts, no swirl, no lights, just clean subject separation that follows natural depth (nearer objects blur less than distant ones). It's the fix for photos where the background competes with the person, which is most photos taken indoors, in crowds, or in kitchens.