Refresh MiniMax preset and docs

[octo-patch]

Reason: refresh the MiniMax preset and docs for the current M3/M2.7 models and both API hosts

• update the MiniMax generic provider preset to use MiniMax-M3, the global API host, and the current docs URL while still matching the China host
• refresh the MiniMax setup docs and generic-provider examples with MiniMax-M3, MiniMax-M2.7, their current context windows, and both API hosts
• update the doc site catalog and landing card so the public docs point at the refreshed MiniMax defaults

Checks:

• npm test -- providers.presets.test.ts
• npm run build
• npm --prefix docweb run build
• git diff HEAD --no-ext-diff | grep -E "$SECRET_RE"