Model defs for Sonnet 5/4.6 are missing thinkingLevelMap

[elidickinson]

What happened?

Sonnet 5 and Sonnet 4.6 are missing thinkingLevelMap in anthropic.models.ts, so
getSupportedThinkingLevels() hides xhigh from the picker (it's opt-in and requires an
explicit mapping unlike every other level).

Both models support effort max as their top tier (confirmed via Claude Code's
supportedModels() API: [low, medium, high, max]). They should get thinkingLevelMap: { xhigh: "max" }, matching opus-4-6 which has the same tier structure.

Fable-5, opus-4-6, opus-4-7, and opus-4-8 all have maps. Only the two Sonnets are
missing.

Steps to reproduce

1. Select claude-sonnet-5 or claude-sonnet-4-6
2. Open the thinking level picker
3. xhigh is missing — only off/minimal/low/medium/high are shown

Expected behavior

No response

Version

No response

[github-actions]

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