Right-size operator registry for embedded targets

[rascani]

Description

Currently, the operator registry size can be controlled via MAX_KERNEL_NUM, which is defaulted to 2000. This is 24 KiB on 32-bit systems. Provide a mechanism to automatically right-size the operator registry based on which kernels are actually needed for a given model.

Acceptance Criteria

• Tool or build step that prunes operator registry to model requirements
• Measurable reduction in RAM usage from registry pruning
• Integrated with selective build workflow