llvm(py): introduce BuildCtx + trace hub; refactor if-merge prepass + PHI wiring into module; unify logs; ctx-enable compare/ret/call/boxcall/externcall/typeop/newbox/safepoint; curated smoke option for if-merge; README updates; keep behavior stable

src/llvm_py/instructions/__init__.py

@@ -7,8 +7,9 @@ Each instruction has its own file, following Rust structure
 from .const import lower_const
 from .binop import lower_binop
 from .compare import lower_compare
-from .jump import lower_jump
-from .branch import lower_branch
+# controlflow
+from .controlflow.jump import lower_jump
+from .controlflow.branch import lower_branch
 from .ret import lower_return
 from .phi import lower_phi
 from .call import lower_call
@@ -29,4 +30,4 @@ __all__ = [
     'lower_externcall', 'lower_typeop', 'lower_safepoint',
     'lower_barrier', 'lower_newbox',
     'LoopFormContext', 'lower_while_loopform'
-]
+]