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_relationship.rs

@@ -30,10 +30,7 @@ fn after_relationship_keyword_offers_from_and_names() {
     assert!(matches!(a.state, InputState::IncompleteAtEof));
     // Both selector forms discoverable: `from` for endpoints,
     // the relationship name for the by-name form.
-    assert_candidate_present(
-        &a,
-        &["from", "Orders_CustId_to_Customers"],
-    );
+    assert_candidate_present(&a, &["from", "Orders_CustId_to_Customers"]);
     crate::snap!("after_relationship_keyword", a);
 }
 
@@ -61,10 +58,7 @@ fn after_parent_table_dot_narrows_to_parent_columns() {
 #[test]
 fn after_to_offers_table_names() {
     let schema = schema_with_relationship();
-    let a = assess_at_end(
-        "drop relationship from Orders.CustId to ",
-        &schema,
-    );
+    let a = assess_at_end("drop relationship from Orders.CustId to ", &schema);
     assert!(matches!(a.state, InputState::IncompleteAtEof));
     assert_candidate_present(&a, &["Customers", "Orders"]);
     crate::snap!("after_to", a);
@@ -98,10 +92,7 @@ fn complete_drop_relationship_by_endpoints_parses() {
 #[test]
 fn complete_drop_relationship_by_name_parses() {
     let schema = schema_with_relationship();
-    let a = assess_at_end(
-        "drop relationship Orders_CustId_to_Customers",
-        &schema,
-    );
+    let a = assess_at_end("drop relationship Orders_CustId_to_Customers", &schema);
     assert!(matches!(a.state, InputState::Valid));
     assert_eq!(a.parse_result.as_deref(), Ok("DropRelationship"));
     crate::snap!("complete_by_name", a);