_read_hub_installed_names() reads ~/.hermes/skills/.hub/lock.json with a
strict utf-8 decode. Hub skill descriptions can carry Windows-1252
typographic bytes (em-dash 0x97, smart quotes, bullets) as single high
bytes; read_text(encoding="utf-8") then raises UnicodeDecodeError, which
is a ValueError sibling not caught by the function's
except (OSError, json.JSONDecodeError). It escapes and 500s the whole
/api/skills endpoint, blanking the desktop Skills panel.
Decode with errors="replace" so the offending byte degrades to U+FFFD
and the structurally valid JSON — and every other skill — stays readable.
Fixes#68053
