[Bug] Model configuration "opusplan" not recognized in plan mode

Bug Description
when i set {
...,
"model": "opusplan"
} in config opus model isn't activated in plan mode. it was working few days ago

Environment Info

• Platform: win32
• Terminal: windows-terminal
• Version: 2.0.76
• Feedback ID: 70b230e4-32a2-4e88-9806-0bb0d17855b5

Errors

[{"error":"SyntaxError: JSON Parse error: Property name must be a string literal\n    at <parse> (:0)\n    at parse (unknown)\n    at <anonymous> (B:/~BUN/root/claude.exe:77:751)\n    at A (B:/~BUN/root/claude.exe:11:6978)\n    at xGE (B:/~BUN/root/claude.exe:2560:26855)\n    at async qxI (B:/~BUN/root/claude.exe:2560:29641)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-01-03T20:30:05.502Z"}]