ocx-* agent note 'pass model: haiku as a placeholder' runs real Haiku outside the proxy #6358

Summary

The NO_MODEL_ARG note appended to every ocx-* agent description (src/claude/agents-inject.ts) tells the dispatcher to pass model: "haiku" as a placeholder because "the model argument is ignored". That is true only when Claude Code runs through the opencodex proxy. When the same ~/.claude/agents/ocx-*.md files are loaded by a Claude Code session that is not routed through the proxy (for example the Claude desktop app), the model argument overrides the agent's model: frontmatter and the subagent really runs on Claude Haiku.

Observed (opencodex 2.73.0, Windows)

• Agent file ocx-gpt-6-1-sol.md pins model: "ocx-claude-native--gpt-6.1-sol".
• The dispatcher followed the description and passed model: "haiku".
• The subagent ran as Claude Haiku 4.5 and returned a review labelled "GPT-6.1 Sol"; the substitution was silent.

Suggested fix

• Reword the note so it is safe in both cases, e.g. "omit the model argument; outside the opencodex proxy it overrides the pin", or
• only emit the placeholder instruction when the injected agents are used by a proxied session (or write the ocx agents to a proxy-only agents directory).

Related: #252 (placeholder label choice).