v3 : relecture de a576b68 — les propositions retirées sortent de la médiane, les réglages montrent la vraie participation

La médiane de participation ne compte plus les propositions retirées (invisibles, votes
non repris). Quand l'échelle ramène la participation dans ses bornes, les réglages disent
la médiane mesurée (ou deux fois C) et, à part, la valeur sur laquelle les seuils se calculent.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/ld-server/tests/inertia.rs

@@ -274,6 +274,42 @@ async fn the_usual_participation_is_the_median_of_five_voted_proposals() {
     );
 }
 
+#[tokio::test]
+async fn a_withdrawn_proposal_leaves_the_usual_participation() {
+    // Relecture of a576b68: withdrawn proposals vanish from the document and their
+    // votes can no longer be taken back, so they must not weigh on the median.
+    let (mut first, state) = Client::new().await;
+    let mut people = Vec::new();
+    for name in ["W1", "W2", "W3", "W4"] {
+        let mut c = first.other();
+        c.login(name).await;
+        people.push(c);
+    }
+    first.login("W1").await;
+    let doc = first.doc("essai").await;
+    let open: Vec<String> = ["I2", "T1", "E4", "E5", "E6"]
+        .iter()
+        .map(|code| unit(&doc, code)["proposals"][0]["id"].as_str().expect("open").to_owned())
+        .collect();
+    for p in &open {
+        for c in people.iter_mut().take(2) {
+            c.vote(p, "against").await;
+        }
+    }
+    ld_server::participation::refresh(&state, true).await.expect("refresh");
+    let p = first.doc("essai").await["doc"]["participation"].clone();
+    assert_eq!((p["source"].as_str(), p["sample"].as_u64()), (Some("median"), Some(5)));
+
+    sqlx::query("UPDATE proposals SET status = 'withdrawn' WHERE id = ?")
+        .bind(&open[0])
+        .execute(&state.db)
+        .await
+        .expect("withdraw");
+    ld_server::participation::refresh(&state, true).await.expect("refresh");
+    let p = first.doc("essai").await["doc"]["participation"].clone();
+    assert_eq!((p["source"].as_str(), p["sample"].as_u64()), (Some("reference"), Some(4)));
+}
+
 // ---------------------------------------------------------------------------
 // The base as production holds it on 2026-10-30, then the new version
 // ---------------------------------------------------------------------------