feat(fifa17): own club/stats/staff (empty stat set) in Rust

Migrate GET club/stats/staff from the Python proxy to a Rust static handler.
The production oracle returns {} for the staff-bonus stat set (deliberately
empty); the Rust host now owns it (owner=RUST route=club-stats-staff). Updates
classify(), the pre-existing near-miss test (now club/stats/year), the ownership
matrix test, and the no-fallback integration test. club/stats/{year,consumables}
remain Python (aggregation) pending the Core-derived club-stats migration.

openfut-adapter-fifa17/src/fut/non_economy.rs

@@ -40,6 +40,12 @@ pub fn match_reset_body() -> Value {
     json!({})
 }
 
+/// `GET …/club/stats/staff` — production oracle returns an empty object (FIFA's
+/// staff-bonus stat set is deliberately empty; the client tolerates `{}`).
+pub fn club_stats_staff_body() -> Value {
+    json!({})
+}
+
 /// The phishing/security-question action, parsed from the URL tail.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum SecurityAction {
@@ -140,6 +146,7 @@ mod tests {
         assert_eq!(settings_body(), json!({ "configs": [] }));
         assert_eq!(leaderboard_options_body(), json!({}));
         assert_eq!(match_reset_body(), json!({}));
+        assert_eq!(club_stats_staff_body(), json!({}));
     }
 
     #[test]