fix: validate ParameterDef.bounds types at construction

[rororowyourboat]

Problem

packages/gds-framework/gds/parameters.py:33 — bounds: tuple[Any, Any] accepts any types. Passing non-comparable values like ("string", object()) will crash at low <= value <= high with a TypeError at runtime.

Fix

Add a @model_validator that checks bounds are comparable (both same type, or both support __le__). Alternatively, constrain the type to tuple[float, float] | tuple[int, int] | None.