mito-ai: remove sonnet

[aarondr77]

Description

Please include a summary of the change and which issue is fixed. Please also include relevant motivation and context, and the specification if there is one.

Testing

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• I have tested this on real data that is reasonable and large
• If I changed the interaction with JupyterLab, I tested that it does not break other programs (like VS Code), and tested that it works "multiple times" in the same notebook.

Documentation

Note if any new documentation needs to addressed or reviewed.

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Note

Medium Risk
Medium risk because it changes the set/order of supported Anthropic models across backend and UI, which can affect saved configurations and large-context fallback behavior.

Overview
Removes claude-sonnet-4-5-20250929 from the supported/advertised model lists and UI model picker, leaving Claude Haiku as the only standard Anthropic option.

Updates backend model ordering/standard model lists and refreshes unit/UI/e2e tests to use Haiku everywhere (including provider selection, Mito-server fallback, and ModelSelector localStorage expectations). Also drops the unused FAST_ANTHROPIC_MODEL constant while keeping Sonnet only as the internal LARGE_CONTEXT_MODEL for extended-context selection.

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Project	Deployment	Actions	Updated (UTC)
monorepo	Ready	Preview, Comment	Feb 3, 2026 4:03pm

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