Implement Misses DSL compiler (parser + codegen)

- ast.rs: Full AST for .mrs files (MacroDef, Pattern, OutputBody, TemplateItem)
- parser.rs: Hand-written recursive descent parser with line/col error reporting
- codegen.rs: Transforms AST to Rust proc macro code using syn/quote/proc_macro2
- main.rs: CLI reads .mrs file, runs parse→codegen, writes to stdout or file
- Cargo.toml: Workspace with syn, quote, proc-macro2, prettyplease deps
- examples/: hello.mrs, derive_builder.mrs, declare_table.mrs reference examples

All three reference examples parse and produce prettyplease-formatted Rust output.
Generated code uses syn::parse::Parser closures for structural patterns, quote!
for token templates, spread iteration via .iter().map().collect(), and
format_ident! for identifier construction.

https://claude.ai/code/session_01Tppkab4eLsL21asHGjQJoF

examples/hello.mrs

@@ -0,0 +1,9 @@
+macro hello! {
+    $name:ident => {
+        T~{
+            pub fn #[say => hello]() -> &'static str {
+                ${ format!("hello, {}!", stringify!(name)) }
+            }
+        }
+    }
+}