chore: remove dead Python SDK code, simplify Input(), patch FieldInfo defaults in Rust
Dead code removed:
- schema.py (PredictionRequest/Response — unused)
- suppress_output.py (never imported)
- command/ directory (legacy schema gen entry point — already deleted)
- PredictorNotSet exception, get_predictor_types, requires_gpu (config.py)
- get_predict, get_train, wait_for_env, get_healthcheck (predictor.py)
- put_file_to_signed_endpoint, guess_filename, ensure_trailing_slash (files.py)
- ExperimentalFeatureWarning (types.py)
Input() changes:
- default_factory now raises TypeError at class definition time
- Stripped all mutable-default/factory machinery from Input()
- Schema-gen already errors on default_factory at build time
FieldInfo default patching (coglet predictor.rs):
- At predictor load time, replaces FieldInfo defaults with their .default
values on predict/train method signatures so Python uses actual defaults
instead of FieldInfo wrapper objects for missing inputs