Fix dashboard imports for Streamlit multi-page routing

- Add sys.path.insert at top of app.py and all 5 page files
- Fix .streamlit/config.toml CORS/XSRF conflict
- Remove duplicate st.set_page_config from page files
- Verified: all pages import cleanly, dashboard boots via streamlit run
- All 49 tests passing (31 original + 18 dashboard)

dashboard/pages/04_lineup.py

@@ -1,3 +1,4 @@
+import sys; from pathlib import Path; _p = Path(__file__).resolve().parent.parent.parent; str(_p) not in sys.path and sys.path.insert(0, str(_p))
 """Page 4 — Lineup Optimizer.
 
 SVG pitch with optimal XI, what-if toggles, opponent mirror.
@@ -84,7 +85,6 @@ def _opponent_lineup(preds, fixtures):
 
 
 def run():
-    st.set_page_config(page_title="Lineup — Fantabeto", page_icon="📋", layout="wide")
     inject_css()
     preds, fixtures, players = _get_data()