Add property accessors to RealModelStack for interface parity

RealModelStack stored models in self.models dict but lacked property
accessors that pipeline code expected. MockModelStack exposes models
as direct attributes (self.vision, etc.) but RealModelStack did not.

This fix adds @property accessors for vision, embedding, and reranker
that wrap the raw models in their respective wrapper classes, making
RealModelStack API-compatible with MockModelStack.

Fixes: 'RealModelStack' object has no attribute 'vision' error

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

models/real.py

@@ -110,6 +110,21 @@ class RealModelStack:
         """Check if models are loaded."""
         return self.loaded
 
+    @property
+    def vision(self) -> "RealVisionModel":
+        """Return vision model wrapped for pipeline consumption."""
+        return RealVisionModel(self.models["vision"], self.processors["vision"])
+
+    @property
+    def embedding(self) -> "RealEmbeddingModel":
+        """Return embedding model wrapped for pipeline consumption."""
+        return RealEmbeddingModel(self.models["embedding"], self.processors["embedding"])
+
+    @property
+    def reranker(self) -> "RealRerankerModel":
+        """Return reranker model wrapped for pipeline consumption."""
+        return RealRerankerModel(self.models["reranker"], self.processors["reranker"])
+
 
 class RealVisionModel:
     """Wrapper for real vision model inference."""