Problem

Delegated tasks currently capture the parent session model, but unconfigured subagents/categories still resolve to their own built-in defaults instead of following the parents current effective model.

This makes model choice inconsistent at runtime:

• explicit agent/category model overrides still make sense
• but when no explicit model is configured, users expect delegated tasks to follow the model that the parent session is already using

Expected behavior

Model resolution should use this precedence:

1. explicit user-configured subagent/category model
2. inherited parent session effective model
3. existing built-in category/agent default
4. existing fallback chain / system default behavior

Why this matters

This would let users switch the main orchestrator model at runtime without having every unconfigured delegated task unexpectedly snap back to hardcoded defaults.

Notes

I have a local patch and regression tests prepared for delegate-task that implement this precedence without overriding explicit config.