style: Migrate to stable-only rustfmt configuration

- Remove nightly-only features from .rustfmt.toml and vendor/ss58-registry/rustfmt.toml
- Removed features: imports_granularity, wrap_comments, comment_width,
  reorder_impl_items, spaces_around_ranges, binop_separator,
  match_arm_blocks, trailing_semicolon, trailing_comma
- Format all 898 affected files with stable rustfmt
- Ensures long-term reliability without nightly toolchain dependency

pezkuwi/node/core/chain-selection/src/db_backend/v1.rs

@@ -290,7 +290,7 @@ impl Backend for DbBackend {
 						block_entry.encode(),
 					);
 				},
-				BackendWriteOp::WriteBlocksByNumber(block_number, v) =>
+				BackendWriteOp::WriteBlocksByNumber(block_number, v) => {
 					if v.is_empty() {
 						tx.delete(self.config.col_data, &block_height_key(block_number));
 					} else {
@@ -299,7 +299,8 @@ impl Backend for DbBackend {
 							&block_height_key(block_number),
 							v.encode(),
 						);
-					},
+					}
+				},
 				BackendWriteOp::WriteViableLeaves(leaves) => {
 					let leaves: LeafEntrySet = leaves.into();
 					if leaves.inner.is_empty() {

pezkuwi/node/core/chain-selection/src/tree.rs

@@ -224,10 +224,11 @@ fn propagate_viability_update(
 				// finalized block is implicitly the viable leaf.
 				continue;
 			},
-			Some(entry) =>
+			Some(entry) => {
 				if entry.children.len() == pivot_count {
 					viable_leaves.insert(entry.leaf_entry());
-				},
+				}
+			},
 		}
 	}