F1 sprint constructor/team pick submission

OVERRIDES runtime profile: uses no Claude model — pure Python Playwright script, no LLM calls.

Saturday 04:00 and 06:00 SAST (02:00/04:00 UTC) sprint pick submission guard windows for sprint weekends.

Designed to run before each sprint weekend's Sprint session start (sprint_utc in the calendar). Submits the sprint constructor/team pick to Superbru via .motorsport-team-option selector.

Pool field is team-only. The current Superbru pool's sprint field is "which team earns most points in the Sprint?" — there is NO driver sprint-winner picker. The pipeline may still derive a driver sprint-winner signal for analysis (sprint_prediction[]), but only the team field is submitted. If the live Superbru page ever adds a driver field, update the selector logic + extend coverage in tests/test_sprint_winner.py before changing submission behaviour.

Race picks (Pole, positions 1-10, FL) are submitted separately by the Saturday prediction task (f1-prediction-saturday) before each race's qualifying_utc.

The early 04:00 SAST guard covers sprint deadlines as early as China 03:00 UTC; the 06:00 SAST guard preserves the previous later-Saturday visibility window. The script checks sprint_window_open() first — exits cleanly if no sprint race or sprint deadline already passed. Safe to run on non-sprint weekends and noisy- safe because closed-window runs do not submit. Dry-run / no-submit validation must be used before changing selectors or submission behaviour; no Superbru writes happen in tests.

Requires: prediction pipeline must have run first (f1-prediction Thursday task). If final_prediction.json is missing, alerts via Telegram and exits 1.