fix(supervisor): use file path for export_serving (not -m module syntax)

-m padelnomics.export_serving resolves to web package, not src/padelnomics.
src/padelnomics is not a uv workspace member so it's not importable by name.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

infra/supervisor/supervisor.sh

@@ -42,7 +42,7 @@ do
         # The web app detects the inode change on next query — no restart needed.
         DUCKDB_PATH="${DUCKDB_PATH:-/data/padelnomics/lakehouse.duckdb}" \
         SERVING_DUCKDB_PATH="${SERVING_DUCKDB_PATH:-/data/padelnomics/analytics.duckdb}" \
-            uv run python -m padelnomics.export_serving
+            uv run python src/padelnomics/export_serving.py
 
     ) || {
         if [ -n "${ALERT_WEBHOOK_URL:-}" ]; then