feat(workflow): simplify article flow and add automated rewrite step

backend/app/workflow.py

@@ -0,0 +1,39 @@
+from __future__ import annotations
+
+UI_STATUSES = ("new", "rewrite", "publish", "published", "close")
+
+
+def internal_to_ui_status(status: str | None) -> str:
+    value = (status or "").strip()
+    if value == "approved":
+        return "publish"
+    if value == "error":
+        return "close"
+    if value == "review":
+        return "rewrite"
+    if value in {"new", "rewrite", "published"}:
+        return value
+    return value or "new"
+
+
+def ui_to_internal_status(status: str | None) -> str:
+    value = (status or "").strip()
+    if value == "publish":
+        return "approved"
+    if value == "close":
+        return "error"
+    if value in {"new", "rewrite", "published"}:
+        return value
+    if value in {"approved", "error", "review"}:
+        return value
+    return value
+
+
+ALLOWED_UI_TRANSITIONS: dict[str, set[str]] = {
+    "new": {"rewrite", "close"},
+    "rewrite": {"publish", "close"},
+    "publish": {"published", "close"},
+    "published": {"close"},
+    "close": {"rewrite"},
+}
+