Add TextFSM rule tables as dual input to biz-state parsers.

Collectors apply RULE_KEYS (or index stems) into fsm_tables before normalize; parsers prefer FSM or hand-parse.

Co-authored-by: Cursor <cursoragent@cursor.com>

netx_api/biz_state/parsers/common/pipeline.py

@@ -0,0 +1,31 @@
+"""Shared FSM-vs-hand helpers for biz_state parsers."""
+
+from __future__ import annotations
+
+from typing import Any, Callable, Mapping, Sequence
+
+MapRowsFn = Callable[[list[dict[str, Any]]], list[dict[str, Any]]]
+HandFn = Callable[..., list[dict[str, Any]]]
+
+
+def prefer_fsm(
+    fsm_tables: Mapping[str, list[dict[str, Any]]] | None,
+    keys: Sequence[str],
+    map_rows: MapRowsFn,
+    hand_fn: HandFn,
+    *,
+    raw_text: str,
+    **kw: Any,
+) -> list[dict[str, Any]]:
+    """Use the first non-empty FSM table (mapped); otherwise hand-parse raw_text."""
+    tables = fsm_tables or {}
+    for key in keys or ():
+        k = str(key or "").strip()
+        if not k:
+            continue
+        rows = tables.get(k) or []
+        if rows:
+            mapped = map_rows(rows)
+            if mapped:
+                return mapped
+    return hand_fn(raw_text=raw_text, **kw)