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/naming.rs

@@ -17,8 +17,8 @@
 
 use std::path::Path;
 
-use rand::seq::IndexedRandom;
 use rand::Rng;
+use rand::seq::IndexedRandom;
 
 const WORDLIST: &str = include_str!("wordlist.txt");
 const MAX_COLLISION_RETRIES: usize = 100;
@@ -41,10 +41,9 @@ pub enum NamingError {
 impl std::fmt::Display for NamingError {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
-            Self::WordlistTooSmall(n) => f.write_str(&crate::t!(
-                "project.naming.wordlist_too_small",
-                count = n,
-            )),
+            Self::WordlistTooSmall(n) => {
+                f.write_str(&crate::t!("project.naming.wordlist_too_small", count = n,))
+            }
             Self::TooManyCollisions(n) => f.write_str(&crate::t!(
                 "project.naming.too_many_collisions",
                 attempts = n,
@@ -189,10 +188,9 @@ impl std::fmt::Display for UserNameError {
         match self {
             Self::Empty => f.write_str(&crate::t!("project.user_name.empty")),
             Self::LeadingDot => f.write_str(&crate::t!("project.user_name.leading_dot")),
-            Self::InvalidChar(c) => f.write_str(&crate::t!(
-                "project.user_name.invalid_char",
-                ch = c,
-            )),
+            Self::InvalidChar(c) => {
+                f.write_str(&crate::t!("project.user_name.invalid_char", ch = c,))
+            }
         }
     }
 }
@@ -209,14 +207,22 @@ mod tests {
     #[test]
     fn wordlist_has_enough_entries() {
         let pool = words();
-        assert!(pool.len() >= 100, "wordlist suspiciously small: {} entries", pool.len());
+        assert!(
+            pool.len() >= 100,
+            "wordlist suspiciously small: {} entries",
+            pool.len()
+        );
     }
 
     #[test]
     fn wordlist_has_no_duplicates() {
         let pool = words();
         let unique: std::collections::HashSet<_> = pool.iter().collect();
-        assert_eq!(unique.len(), pool.len(), "wordlist contains duplicate entries");
+        assert_eq!(
+            unique.len(),
+            pool.len(),
+            "wordlist contains duplicate entries"
+        );
     }
 
     #[test]
@@ -290,7 +296,7 @@ mod tests {
         assert!(!is_temp_dirname("MyOrders"));
         assert!(!is_temp_dirname("term_planner"));
         assert!(!is_temp_dirname("20260507-water-buffalo-skating")); // no marker
-        assert!(!is_temp_dirname("temp-project"));                   // no brackets
+        assert!(!is_temp_dirname("temp-project")); // no brackets
     }
 
     #[test]
@@ -301,9 +307,18 @@ mod tests {
         assert!(validate_user_name("project.v2").is_ok());
 
         assert_eq!(validate_user_name(""), Err(UserNameError::Empty));
-        assert_eq!(validate_user_name(".hidden"), Err(UserNameError::LeadingDot));
-        assert!(matches!(validate_user_name("a/b"), Err(UserNameError::InvalidChar('/'))));
-        assert!(matches!(validate_user_name("a b"), Err(UserNameError::InvalidChar(' '))));
+        assert_eq!(
+            validate_user_name(".hidden"),
+            Err(UserNameError::LeadingDot)
+        );
+        assert!(matches!(
+            validate_user_name("a/b"),
+            Err(UserNameError::InvalidChar('/'))
+        ));
+        assert!(matches!(
+            validate_user_name("a b"),
+            Err(UserNameError::InvalidChar(' '))
+        ));
     }
 
     fn tempdir() -> tempfile::TempDir {