Parser: accept ; as optional statement separator

Newlines remain the primary separator, but \`;\` now lets short
statements share a line for readability:

    on frame {
        a += 1; b += 2
        if button.a { a -= 1; b -= 1 }
    }

Implementation: \`parse_block\` consumes any \`;\` tokens between
statements.

https://claude.ai/code/session_01W6eQFStA66EuMKHUFo2rx3

src/parser/mod.rs

@@ -830,6 +830,13 @@ impl Parser {
         let mut statements = Vec::new();
         while *self.peek() != TokenKind::RBrace && *self.peek() != TokenKind::Eof {
             statements.push(self.parse_statement()?);
+            // Allow optional `;` between statements for readability.
+            // Newlines are still the primary separator, but `;` lets
+            // users put short statements on the same line:
+            //   `x += 1; y += 1`
+            while *self.peek() == TokenKind::Semicolon {
+                self.advance();
+            }
         }
         self.expect(&TokenKind::RBrace)?;
 

src/parser/tests.rs

@@ -665,6 +665,27 @@ fn parse_mmc3_mapper() {
     assert_eq!(prog.game.mapper, Mapper::MMC3);
 }
 
+#[test]
+fn parse_semicolon_separators() {
+    // `;` should act as an optional statement separator so short
+    // statements can share a line.
+    let src = r#"
+        game "Test" { mapper: NROM }
+        var a: u8 = 0
+        var b: u8 = 0
+        on frame {
+            a += 1; b += 2
+            if button.a { a -= 1; b -= 1 }
+            wait_frame
+        }
+        start Main
+    "#;
+    let prog = parse_ok(src);
+    let frame = prog.states[0].on_frame.as_ref().unwrap();
+    // Top-level statements: two assigns + if + wait_frame
+    assert_eq!(frame.statements.len(), 4);
+}
+
 #[test]
 fn parse_match_statement() {
     let src = r#"