settings.json "model" field: alias with [1m] suffix rejected by UI but works in CLI

Bug Description

Setting "model": "sonnet[1m]" in ~/.claude/settings.json causes Claude Code UI to display:

"sonnet[1m] em ~/.claude/settings.json não corresponde a um modelo disponível. Atualize a configuração de modelo; usando Opus 4.7 1M por..."

App falls back to Opus 4.7 1M silently.

Steps to Reproduce

1. Set ~/.claude/settings.json:

``json
{
"model": "sonnet[1m]"
}
``

1. Open Claude Code app
2. See warning banner — model "sonnet[1m]" not recognized, fallback to Opus 4.7 1M

Expected Behavior

sonnet[1m] should be recognized as valid alias (same as CLI).

Actual Behavior

UI rejects alias, falls back to Opus 4.7 1M.

Evidence: CLI works fine

$ claude --model 'sonnet[1m]' --print "say ok"
ok
$ claude --model 'claude-sonnet-4-6[1m]' --print "say ok"
ok

Both work in CLI. Full ID claude-sonnet-4-6[1m] also rejected by UI.

Environment

• Claude Code version: 2.1.132
• OS: macOS
• Model attempted: sonnet[1m], claude-sonnet-4-6[1m]

Workaround

None found — neither short alias nor full ID accepted by settings.json parser for Sonnet 1M.