When scheduling a print to "any printer" with a filament color override,
the scheduler picked a printer with the correct filament type but wrong
color. _find_idle_printer_for_model() used color matching only for
ranking candidates, not filtering — a printer with 0 color matches was
still selected if it had the right types.
Now requires at least 1 color match when filament overrides specify
colors. Printers with 0 matches are skipped and reported in the
"waiting for filament" reason instead of being treated as candidates.
maziggy
c770f842f2