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/objective.rs

@@ -67,10 +67,7 @@ pub async fn increment_metric(
 ) -> AppResult<Vec<String>> {
     let mut completed_ids = Vec::new();
 
-    for def in defs
-        .iter()
-        .filter(|d| d.metric.as_str() == metric)
-    {
+    for def in defs.iter().filter(|d| d.metric.as_str() == metric) {
         let existing = sqlx::query_as::<_, ObjectiveProgress>(
             "SELECT id, profile_id, objective_id, current, completed, claimed, updated_at FROM objective_progress WHERE profile_id = ? AND objective_id = ?"
         )