Add direct signal assignment in event handlers

- Handle 'assign' type statements in _emit_handler_statement()
- Evaluate value expression and store to signal global
- Enables patterns like: setting_tab = 0
- All tests passing (30/30)

ritz/llvm_codegen_signals.py

@@ -161,7 +161,19 @@ class SignalLLVMIRGenerator:
 
     def _emit_handler_statement(self, stmt: dict[str, Any]) -> None:
         """Emit a statement inside an event handler."""
-        if stmt["type"] == "augassign":
+        if stmt["type"] == "assign":
+            # Handle direct signal assignment (x = 5)
+            signal_name = stmt["target"]
+            if signal_name in self.signals:
+                # Evaluate the value expression
+                value_var = self._emit_expr(stmt["value"])
+
+                # Store the value
+                self.lines.append(f"  store i32 {value_var}, i32* {self._signal_global(signal_name)}")
+
+                # TODO: Trigger DOM updates
+                self.lines.append(f"  ; TODO: Update DOM nodes bound to {signal_name}")
+        elif stmt["type"] == "augassign":
             # Handle signal updates (count += 1)
             signal_name = stmt["target"]
             if signal_name in self.signals: