Run the full QA cycle. Fix any errors before proceeding.

1. `cargo fmt --check` — if it fails, run `cargo fmt` and restart
2. `cargo clippy -- -D warnings` — fix all warnings
3. `cargo test` — all tests must pass
4. `cargo build --release` — verify release build compiles

If ANY step fails: fix the issue, then restart from step 1.
Only report success when all 4 steps pass consecutively.