fix(detector): detect generator send replay

[prasannakotyal]

KernelGuard-Red-Submission: 86

Adds a narrow LAST_CALL_REPLAY pass for generator .send() state machines that replay the prior output on object-identity match.

The detector requires:

• a generator function that receives a live value through yield assignment
• an identity guard comparing that yielded value to saved state
• a fast-path yield of saved output
• an else update of saved output from the yielded value
• the custom_kernel entrypoint sending its live input into a generator

Local validation:

• UV_CACHE_DIR=/tmp/uvcache uv run python -m py_compile competition_state/kernelguard_mirror/kernelguard.py
• UV_CACHE_DIR=/tmp/uvcache uv run python kernelguard_bypasses/eval_blue_patch.py competition_state/kernelguard_mirror/kernelguard.py
• target artifact /tmp/kg_external_reds/0086_SarahLacard_red-gensend-2026-05-01.py is filtered as LAST_CALL_REPLAY

Target red artifact: SarahLacard red 86, generator .send() state machine.

[github-actions]

KernelGuard Blue Evaluation

• Evaluation job: 170
• Blue submission: 142
• 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/25257401578