[b-re-w]

Closes #323

• Cause: when androidx.compose.ui.Modifier is not yet in sys.modules, 'import androidx.compose.ui.Modifier' creates it through the finder. importlib then binds the module onto the parent (setattr after _load_unlocked), which shadows the proxy class. If the module is already loaded, CPython returns it without touching the parent.
• Fix: the parent's module type guards setattr with class_wins_over_module (from Binder: a public companion object is reachable from Python as a value (Owner.Companion) #322), in the adapter's adapted modules and in PythonProxySource's per-module types. The class stays, and its getattr serves the module's statics. 'import androidx.compose.ui.Modifier as M' therefore binds the class. Reads are unchanged, since only writes go through setattr.
• SPEC U-4: one sentence.
• Tests (WalkedArtifactCompanionHandleTest), each removing the module from sys.modules first to force the finder path:
  • import then from-import gives the class.
  • from-import then import keeps the class.
  • A repeat import with the module already loaded keeps the class.
  • 'import ... as M' gives the class.
    Three of the four fail against the old code. The 'already loaded' case passes there too, as CPython predicts.
• Binder: a companion-object module shadows a same-named factory function (TextRange(2)) #78's callable module (TextRange) is protected by the parent-declaration check. The compose fixture's TextFieldStateRenderTest exercises it and passes.
• Results: artifact fixture 50/50, ksp app 80/80, compose 129/129, python-multiplatform desktopTest 643/643, androidNative compile.