style(core): apply cargo fmt across routes, services, models, tests

Pure rustfmt reflow (import grouping, array/match-arm/call-arg wrapping,
alphabetized module decls, comment realignment). No semantic change:
full-diff and `git diff -w` both confirm logic byte-identical to 271c363;
workspace builds and all 74 core tests pass. Retained pre-existing WIP
brought forward after verification.

src/services/draft.rs

@@ -184,24 +184,32 @@ pub async fn pick_card(
     let (new_candidates, new_status, reward_coins, reward_pack_id, squad_rating, completed_at) =
         if all_filled {
             let (coins, pack, avg) = compute_reward(card_db, &picks);
-            (None, "completed".to_string(), coins, pack, avg, Some(chrono::Utc::now().to_rfc3339()))
+            (
+                None,
+                "completed".to_string(),
+                coins,
+                pack,
+                avg,
+                Some(chrono::Utc::now().to_rfc3339()),
+            )
         } else {
             let min_overall = difficulty_min_overall(&session.difficulty);
             let next_pos = &pick_order[next_index];
             let next_candidates =
                 pick_candidates(card_db, next_pos, min_overall, CANDIDATES_PER_SLOT);
             {
-            let candidates_json = serde_json::to_string(&next_candidates)
-                .map_err(|e| AppError::Internal(anyhow::anyhow!("serialization failed: {e}")))?;
-            (
-                Some(candidates_json),
-                "active".to_string(),
-                0,
-                None,
-                0,
-                None,
-            )
-        }
+                let candidates_json = serde_json::to_string(&next_candidates).map_err(|e| {
+                    AppError::Internal(anyhow::anyhow!("serialization failed: {e}"))
+                })?;
+                (
+                    Some(candidates_json),
+                    "active".to_string(),
+                    0,
+                    None,
+                    0,
+                    None,
+                )
+            }
         };
 
     let picks_json = serde_json::to_string(&picks)
@@ -294,8 +302,7 @@ async fn fetch_session(pool: &Pool, profile_id: &str, session_id: &str) -> AppRe
 }
 
 fn render_session(session: &DraftSession, card_db: &CardDb) -> serde_json::Value {
-    let pick_order: Vec<String> =
-        serde_json::from_str(&session.pick_order).unwrap_or_default();
+    let pick_order: Vec<String> = serde_json::from_str(&session.pick_order).unwrap_or_default();
     let picks: Vec<String> = serde_json::from_str(&session.picks).unwrap_or_default();
     let candidates: Vec<String> = session
         .current_candidates