models can now be marked `deprecated: true` with a `fallback` slug
pointing to a replacement. `resolveCliModel` follows the chain
recursively (with cycle detection) until it finds a non-deprecated
model. this keeps deprecated models in the registry for backward
compatibility instead of removing them.
marks opencode/mimo-v2-pro-free as deprecated with fallback to
opencode/nemotron-3-super-free.
Made-with: Cursor
Colin McDonnell
b8c4d5b716