feat(flywheel): expose incident processing timeline

apps/api/tests/test_incident_timeline_service.py

@@ -0,0 +1,25 @@
+from src.services.incident_timeline_service import STAGE_DEFS, format_ascii_timeline
+
+
+def _stages(status_by_stage: dict[str, str]) -> list[dict]:
+    return [
+        {"stage": stage, "status": status_by_stage.get(stage, "skipped")}
+        for stage, _label in STAGE_DEFS
+    ]
+
+
+def test_format_ascii_timeline_skips_unrecorded_stages() -> None:
+    stages = _stages({
+        "webhook": "completed",
+        "ai_router": "success",
+        "executor": "error",
+        "km": "pending",
+    })
+
+    assert format_ascii_timeline(stages) == (
+        "webhook:ok > ai_router:ok > executor:fail > km:wait"
+    )
+
+
+def test_format_ascii_timeline_has_empty_fallback() -> None:
+    assert format_ascii_timeline(_stages({})) == "webhook:skip > ai:skip > executor:skip"