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/checkin.rs

@@ -1,4 +1,8 @@
-use crate::{db::Pool, error::AppResult, services::{club, pack}};
+use crate::{
+    db::Pool,
+    error::AppResult,
+    services::{club, pack},
+};
 use uuid::Uuid;
 
 const STREAK_COINS: [i64; 7] = [500, 650, 800, 1000, 1200, 1500, 2000];
@@ -8,7 +12,7 @@ const STREAK_7_PACK: &str = "silver_pack";
 #[derive(Debug, serde::Serialize)]
 pub struct CheckinStatus {
     pub available: bool,
-    pub streak_day: i64,   // current streak (1–7 cycle, 0 if never checked in)
+    pub streak_day: i64, // current streak (1–7 cycle, 0 if never checked in)
     pub next_reward_coins: i64,
     pub next_reward_pack: Option<&'static str>,
     pub last_checked_in: Option<String>,
@@ -56,11 +60,7 @@ pub async fn get_status(pool: &Pool, profile_id: &str) -> AppResult<CheckinStatu
     }
 }
 
-pub async fn claim(
-    pool: &Pool,
-    profile_id: &str,
-    club_id: &str,
-) -> AppResult<CheckinResult> {
+pub async fn claim(pool: &Pool, profile_id: &str, club_id: &str) -> AppResult<CheckinResult> {
     let row: Option<(i64, String)> = sqlx::query_as(
         "SELECT streak_day, checked_in_at FROM daily_checkins \
          WHERE profile_id = ? ORDER BY checked_in_at DESC LIMIT 1",
@@ -82,7 +82,10 @@ pub async fn claim(
         }
     }
 
-    let last_streak = row.as_ref().map(|(s, last_at)| compute_next_streak(*s, last_at)).unwrap_or(1);
+    let last_streak = row
+        .as_ref()
+        .map(|(s, last_at)| compute_next_streak(*s, last_at))
+        .unwrap_or(1);
     let idx = (last_streak - 1).rem_euclid(7) as usize;
     let coins = STREAK_COINS[idx];
     let pack_def = if idx == 6 { Some(STREAK_7_PACK) } else { None };