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/drop_column.rs

@@ -63,10 +63,7 @@ fn complete_drop_column_parses() {
 #[test]
 fn drop_column_with_table_keyword_parses() {
     let schema = schema_serial_pk();
-    let a = assess_at_end(
-        "drop column from table Customers: Email",
-        &schema,
-    );
+    let a = assess_at_end("drop column from table Customers: Email", &schema);
     assert!(matches!(a.state, InputState::Valid));
     crate::snap!("with_table_keyword", a);
 }