[Bug] High-effort session tier not propagated to sub-agents with pinned models

Bug Description
▎ Title: high-effort (ultracode) session tier does not propagate to workflow/sub-agent model selection
▎ Version: 2.1.156 · Severity: Medium (silent correctness degradation)
▎
▎ Summary: A high-effort posture (ultracode = "correctness over cost") does not propagate to sub-agents spawned via Workflow/Agent. Built-in agents with a
▎ pinned model (Explore → Haiku 4.5) run cheap regardless of session tier, with no warning. The idiomatic way to satisfy ultracode silently defeats it.
▎
▎ Resolution precedence (the defect): explicit model: > agent's pinned model > inherit session. Because Explore is pinned, it never reaches "inherit
▎ session," and session effort is never consulted.
▎
▎ Evidence (same workflow): Explore + no model: → 642× Haiku 4.5, zero other models. Explore + model:'opus' → 258× Opus 4.8. Run A's
▎ adversarial-verification phase ran pure judgment on Haiku.
▎
▎ Evidence (same workflow): Explore + no model: → 642× Haiku 4.5, zero other models. Explore + model:'opus' → 258× Opus 4.8. Run A's
▎ adversarial-verification phase ran pure judgment on Haiku.
▎
▎ Suggested fixes: (1) under high effort, cheap-pinned built-ins inherit the session model unless model: is set; (2) warn when a sub-agent runs below
▎ session tier; (3) router refuses cheap models for judgment-typed (schema/verification) calls.

Environment Info

• Platform: darwin
• Terminal: ghostty
• Version: 2.1.154
• Feedback ID: 07317c76-3147-4bfd-9756-8e00c9381ec7

Errors

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