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.

tests/typing_surface/rename_change_column.rs

@@ -34,10 +34,7 @@ fn rename_after_old_column_expects_to() {
 #[test]
 fn rename_after_to_is_new_name_slot() {
     let schema = schema_serial_pk();
-    let a = assess_at_end(
-        "rename column in Customers: Email to ",
-        &schema,
-    );
+    let a = assess_at_end("rename column in Customers: Email to ", &schema);
     assert!(matches!(a.state, InputState::IncompleteAtEof));
     crate::snap!("rename_after_to", a);
 }
@@ -45,10 +42,7 @@ fn rename_after_to_is_new_name_slot() {
 #[test]
 fn complete_rename_column_parses() {
     let schema = schema_serial_pk();
-    let a = assess_at_end(
-        "rename column in Customers: Email to ContactEmail",
-        &schema,
-    );
+    let a = assess_at_end("rename column in Customers: Email to ContactEmail", &schema);
     assert!(matches!(a.state, InputState::Valid));
     assert_eq!(a.parse_result.as_deref(), Ok("RenameColumn"));
     crate::snap!("complete_rename", a);
@@ -78,10 +72,7 @@ fn change_after_open_paren_offers_type_candidates() {
 #[test]
 fn complete_change_column_parses() {
     let schema = schema_serial_pk();
-    let a = assess_at_end(
-        "change column in Customers: Email (text)",
-        &schema,
-    );
+    let a = assess_at_end("change column in Customers: Email (text)", &schema);
     assert!(matches!(a.state, InputState::Valid));
     assert_eq!(a.parse_result.as_deref(), Ok("ChangeColumnType"));
     crate::snap!("complete_change", a);