Add MiniMax provider support

[octo-patch]

Reason: Register MiniMax's Anthropic-compatible API and current text models.

• Detect the supported regional Anthropic-compatible endpoints as the MiniMax provider.
• Register MiniMax-M3 as the built-in default and expose MiniMax-M2.7 in the model picker.
• Preserve the supported context windows and thinking modes in local model handling.
• Include the provider in SDK account data and status diagnostics.

Checks:

• git diff --check
• Bun syntax parsing for all modified TypeScript and TSX files
• Bun provider and model assertions
• Secret scan with the supplied regex