style: format the whole tree with cargo fmt (stock defaults, #35)

One-time, mechanical reformat — no functional changes. The tree was not
rustfmt-clean (~1800 hunks across ~100 files); this brings it to stock
`cargo fmt` defaults so a `cargo fmt --check` CI gate can follow.
Behaviour-preserving: 2509 pass / 0 fail / 1 ignored (unchanged baseline),
clippy clean. A .git-blame-ignore-revs entry follows so `git blame`
skips this commit.

src/project/prettifier.rs

@@ -129,7 +129,10 @@ mod tests {
 
     #[test]
     fn strips_date_prefix_from_temp_project_names() {
-        assert_eq!(prettify("20260507-water-buffalo-skating"), "Water Buffalo Skating");
+        assert_eq!(
+            prettify("20260507-water-buffalo-skating"),
+            "Water Buffalo Skating"
+        );
     }
 
     #[test]
@@ -205,6 +208,9 @@ mod tests {
 
     #[test]
     fn handles_mixed_separators_and_case() {
-        assert_eq!(prettify("MyTeam_lessonPlan-2026"), "My Team Lesson Plan 2026");
+        assert_eq!(
+            prettify("MyTeam_lessonPlan-2026"),
+            "My Team Lesson Plan 2026"
+        );
     }
 }