M10: ProcessingRunner skeleton

- Add modules/runtime/runner.py with ProcessingRunner and ProcessingRequest
- Wire process_images to delegate through runner (internal only)
- Add test/quality/test_processing_runner.py contract test

Behavior-preserving. Zero blast radius. All callers unchanged.

Made-with: Cursor

test/quality/test_processing_runner.py

@@ -0,0 +1,26 @@
+"""Contract tests for ProcessingRunner (M10 runner skeleton)."""
+import modules.processing
+from modules.runtime.runner import ProcessingRunner, ProcessingRequest
+
+
+def test_processing_runner_delegates(monkeypatch):
+    """ProcessingRunner.run delegates to process_images_inner."""
+    called = {}
+
+    def fake_process_images_inner(p):
+        called["ok"] = True
+        return "result"
+
+    monkeypatch.setattr(
+        modules.processing,
+        "process_images_inner",
+        fake_process_images_inner,
+    )
+
+    runner = ProcessingRunner()
+    request = ProcessingRequest(processing="dummy")
+
+    result = runner.run(request)
+
+    assert called["ok"]
+    assert result == "result"