[Bug] Opus 4.6 default model alias not using 1M context window

Bug Description
On Claude 2.1.76 with the Max plan, Opus 4.6 is supposed to default to 1M context window. However, my agents that use Opus by default (model:opus) still use the 200K context window, I have to change it to opus[1M] to enable the full window. This seems unintuitive considering this is now "default".

Environment Info

• Platform: linux
• Terminal: kitty
• Version: 2.1.76
• Feedback ID: 16c3d467-cf1d-4a02-94d2-5617c50541e9

Errors

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