Phase 7E: Autonomy level and sync frequency onboarding UI

## Phase 7E — Autonomy Level & Sync Frequency Onboarding UI ### Context Step 3 (final) of the onboarding wizard. Users choose their autonomy level and how often Scout checks their monitored issues. After completing this step, Scout is fully configured. ### Design philosophy **Light. Precise. Technical. Quiet.** The L3 warning must be explicit — not a tooltip, a visible confirmation. ### Scope Create `apps/web/src/pages/onboarding/Autonomy.tsx` **Autonomy Level (required, radio cards):** - **L1 — Manual**: Every comment requires your explicit approval before posting. - **L2 — Auto-Draft**: Scout prepares drafts. You click Post when ready. - **L3 — Autonomous**: Scout posts within your policy rules automatically. (Requires confirmation.) **Monitoring Frequency (required, select):** - Every 1 hour - Every 6 hours ← default - Every 12 hours - Daily **L3 Confirmation (inline — not a separate modal):** Show a visible checkbox that must be checked before L3 can be saved: > [ ] I understand Scout will post comments on GitHub on my behalf without per-action approval. My policy rules and safety gate remain enforced. **On complete:** Save to `autonomy_policies`, redirect to Radar. ### Acceptance criteria - [ ] Component at correct path - [ ] L1/L2/L3 radio cards work - [ ] Sync frequency selection works (4 options) - [ ] L3 requires the confirmation checkbox before saving - [ ] Saves autonomy level AND sync frequency together - [ ] Redirects to Radar on complete - [ ] Follows design philosophy