Scheduled task ignores model setting, always runs Sonnet

Bug Description

Scheduled tasks always run with Sonnet regardless of model configuration. The model setting in the task edit UI and SKILL.md frontmatter are both ignored.

Steps to Reproduce

1. Create a scheduled task in Claude Code Desktop
2. Open Edit screen → change model dropdown to "Opus 4.6 (1M context)" → Save
3. Run the task via "Run now"
4. Observe: the task session shows "Sonnet 4.6" in the bottom-right model indicator

Additional Attempts

• Added model: opus to SKILL.md frontmatter → still runs Sonnet
• Changed model dropdown in the running session → next run still starts with Sonnet
• Verified no ANTHROPIC_MODEL environment variable is set
• Verified no model override in ~/.claude/settings.json

Expected Behavior

Task should run with Opus as configured in the edit screen and/or SKILL.md frontmatter.

Actual Behavior

Task always starts with Sonnet regardless of configuration.

Environment

• Claude Code Desktop (Mac)
• Max plan
• macOS