feat(runtime): capture step evidence in console

tests/test_timeline.py

@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+from pathlib import Path
+
 from storage.artifact_store import ArtifactStore
 from storage.timeline import Timeline
 from tests.fakes import PNG_10X20
@@ -52,3 +54,32 @@ def test_timeline_records_per_step_prompt_not_task_goal(tmp_path) -> None:
     assert len(records) == 1
     assert records[0]["prompt"] == per_step_prompt
     assert "Call exactly one tool" in records[0]["prompt"]
+
+
+def test_timeline_records_before_and_after_screenshots_with_ocr(tmp_path) -> None:
+    timeline = Timeline(ArtifactStore(tmp_path / "history"))
+    before = b"before-image"
+    after = b"after-image"
+
+    timeline.append(
+        task_id="task-evidence",
+        scene={"screen": {"width": 1, "height": 1}, "elements": []},
+        prompt="goal",
+        tool_call={"action": "tap", "description": "tap search"},
+        result={"ok": True},
+        before_screenshot=before,
+        after_screenshot=after,
+        ocr_results=[
+            {
+                "text": "Search",
+                "confidence": 0.98,
+                "bounds": {"x": 1, "y": 2, "width": 3, "height": 4},
+            }
+        ],
+    )
+
+    record = timeline.read("task-evidence")[0]
+    assert Path(record["before_screenshot_path"]).read_bytes() == before
+    assert Path(record["after_screenshot_path"]).read_bytes() == after
+    assert record["screenshot_path"] == record["after_screenshot_path"]
+    assert record["ocr_results"][0]["text"] == "Search"