parser(match): add MVP type patterns (IntegerBox(x)/StringBox(s)) via AST If-chain; keep literal-only path using PeekExpr; add smoke app (apps/tests/match_type_pattern_basic.nyash); build + stage-2 smokes green

src/parser/declarations/mod.rs

@@ -6,6 +6,7 @@
  */
 
 pub mod box_definition;
+pub mod box_def;
 pub mod dependency_helpers;
 pub mod static_box;