fix(detector): detect while state replay

[prasannakotyal]

KernelGuard-Red-Submission: 313

Adds a narrow LAST_CALL_REPLAY pass for first-call state replay hidden inside a while loop.

The detector requires:

• a loop in the entrypoint that assigns a state slot from a live input-derived expression
• a break guard checking the same state slot against None
• a later return of that same state slot

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/0313_SarahLacard_red-p-143.py is filtered as LAST_CALL_REPLAY

Target red artifact: SarahLacard red 313, while-loop first-call state replay variant.

[github-actions]

KernelGuard Blue Evaluation

• Evaluation job: 174
• Blue submission: 146
• 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/25257495681