refactor: convert inserter module to package with wayland backend

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

whisper_local/inserter/__init__.py

@@ -0,0 +1,19 @@
+"""Text-Einfügung — plattformspezifische Backends hinter gemeinsamem Interface."""
+
+import sys
+from typing import Protocol, runtime_checkable
+
+
+@runtime_checkable
+class Inserter(Protocol):
+    async def insert(self, text: str) -> None: ...
+
+
+def create_inserter() -> Inserter:
+    """Erstellt den plattformspezifischen Inserter."""
+    if sys.platform == "linux":
+        from whisper_local.inserter._wayland import WaylandInserter
+        return WaylandInserter()
+    else:
+        from whisper_local.inserter._win32 import Win32Inserter
+        return Win32Inserter()