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/persistence/mod.rs

@@ -368,12 +368,11 @@ impl Persistence {
             path: data_dir.clone(),
             source,
         })?;
-        let body =
-            csv_io::serialize_table(table).map_err(|message| PersistenceError::Encode {
-                kind: "CSV",
-                path: data_dir.join(format!("{}.csv", table.name)),
-                message,
-            })?;
+        let body = csv_io::serialize_table(table).map_err(|message| PersistenceError::Encode {
+            kind: "CSV",
+            path: data_dir.join(format!("{}.csv", table.name)),
+            message,
+        })?;
         atomic_write(&data_dir.join(format!("{}.csv", table.name)), &body)
     }
 
@@ -406,11 +405,8 @@ impl Persistence {
     ) -> Result<(), PersistenceError> {
         let path = self.project_path.join(HISTORY_LOG);
         let status = history::status_token(history::STATUS_OK, advanced);
-        let line = history::format_record_with_status(
-            command_text,
-            history::utc_iso8601_now(),
-            &status,
-        );
+        let line =
+            history::format_record_with_status(command_text, history::utc_iso8601_now(), &status);
         debug!(
             len = command_text.len(),
             advanced, "persist: append ok record to history.log"
@@ -432,11 +428,8 @@ impl Persistence {
     ) -> Result<(), PersistenceError> {
         let path = self.project_path.join(HISTORY_LOG);
         let status = history::status_token(history::STATUS_ERR, advanced);
-        let line = history::format_record_with_status(
-            command_text,
-            history::utc_iso8601_now(),
-            &status,
-        );
+        let line =
+            history::format_record_with_status(command_text, history::utc_iso8601_now(), &status);
         debug!(
             len = command_text.len(),
             advanced, "persist: append err record to history.log"
@@ -531,8 +524,14 @@ mod tests {
 
     #[test]
     fn extension_with_tmp_appends_to_existing_extension() {
-        assert_eq!(extension_with_tmp(Path::new("a/b/project.yaml")), "yaml.tmp");
-        assert_eq!(extension_with_tmp(Path::new("a/b/Customers.csv")), "csv.tmp");
+        assert_eq!(
+            extension_with_tmp(Path::new("a/b/project.yaml")),
+            "yaml.tmp"
+        );
+        assert_eq!(
+            extension_with_tmp(Path::new("a/b/Customers.csv")),
+            "csv.tmp"
+        );
         assert_eq!(extension_with_tmp(Path::new("a/b/lockfile")), "tmp");
     }
 
@@ -600,7 +599,8 @@ mod tests {
     fn append_history_creates_and_appends() {
         let dir = tempdir();
         let p = Persistence::new(dir.path().to_path_buf());
-        p.append_history("create table Foo with pk id(serial)", false).unwrap();
+        p.append_history("create table Foo with pk id(serial)", false)
+            .unwrap();
         p.append_history("insert into Foo (1)", false).unwrap();
         let body = fs::read_to_string(dir.path().join(HISTORY_LOG)).unwrap();
         let lines: Vec<&str> = body.trim_end().lines().collect();