Implemented and validated.

### Files created
- `/private/tmp/ddc0f4d0/fusion-harness/bench.py`
- `/private/tmp/ddc0f4d0/fusion-harness/RESULTS.md` — generated from fresh measurements

### Commands run
- `uv run bench.py` before implementation — RED as expected because `bench.py` did not exist
- `uv run bench.py` after implementation — completed in 6.765 seconds
- Independent stdlib AST/results validation — PASS

### Measured winners
- **Speed Winner:** `set_based_ctes` — 0.1636s, 1194.12× faster than projected naive autocommit
- **Memory Winner:** `max_tuned_gen` — 25.756 MB measured peak RSS

All seven planned strategies have measured timing and isolated-process peak-RAM results in `RESULTS.md`.