Support multiple components in single file with scoped signals

- Update generate_llvm_ir() to accept list of component dicts
- Process each component with own signal/handler state
- Scope signal globals with component name prefix (@signal_ComponentName_signalName)
- Add _signal_global() helper for scoped signal names
- Update tests for scoped signal names
- All tests passing (30/30)

tests/test_llvm_codegen_conditional.py

@@ -21,8 +21,8 @@ def Toggle():
     ir = parse_component(source)
     llvm_ir = generate_llvm_ir(ir)
 
-    # Should have signal global
-    assert "@signal_visible = global i32 1" in llvm_ir
+    # Should have signal global (scoped to component)
+    assert "@signal_Toggle_visible = global i32 1" in llvm_ir
 
     # Should have conditional branch
     assert "br i1" in llvm_ir