Filter the ACP model picker's list by services.hyperhive.agent.availableModels: an
unconfigured agent (env absent) shows every model the session offers, a
configured list narrows the picker to whatever it names that the session
also offers (in the session's own order), and a configured list matching
none of the session's models (the claude names on an ACP agent that never
touched the option) falls back to showing everything, with one warning
naming the mismatch.
The nix option's default, the model-vs-availableModels build assertion and
hive-subagent-mcp's check_model rail are unchanged — this only touches the
web UI's picker.
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