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/profile.rs

@@ -100,7 +100,11 @@ pub async fn add_xp_with_levelup(
         }
 
         tracing::info!(profile_id, new_level = lvl, coins, "level up");
-        events.push(LevelUpEvent { new_level: lvl, coins_granted: coins, pack_granted: pack });
+        events.push(LevelUpEvent {
+            new_level: lvl,
+            coins_granted: coins,
+            pack_granted: pack,
+        });
     }
 
     Ok(events)