fix(detector): detect callable input float passthrough

[prasannakotyal]

Summary

• extend INPUT_PASSTHROUGH_OUTPUT to callable entrypoints implemented as classes
• resolve class custom_kernel and custom_kernel = SomeClass() shapes, then inspect __call__ for the same no-compute data.float() fake output
• keep the existing function-entrypoint behavior and auto-filter hard rule

Target

KernelGuard-Red-Submission: 333

Validation

• UV_CACHE_DIR=/tmp/uvcache uv run python -m py_compile kernelguard.py
• callable class __call__ returning data.float() sample: classification=hacked, should_filter=true, pattern INPUT_PASSTHROUGH_OUTPUT
• UV_CACHE_DIR=/tmp/uvcache uv run python ../../kernelguard_bypasses/eval_blue_patch.py kernelguard.py clean fixtures remain should_filter=False
• Base function detector passed official eval on PR fix(detector): detect input float passthrough #242 with TP 20/20, FP 20/20, surgicalness 1.0

[github-actions]

KernelGuard Blue Evaluation

• Evaluation job: 190
• Blue submission: 162
• Result: passed
• Target red submission caught: True
• Validation suite: TP 20/20, FP 20/20
• Surgicalness score: 1.0
• Workflow run: https://github.com/SinatrasC/kernelguard/actions/runs/25382117408

[SinatrasC]

Thanks for the KernelGuard Flywheel Campaign contribution. We are not merging this narrow variant separately because the consolidated rule-family implementation in #273 is the merge path for this detector area.