feat: embed gf3 water extraction workflow

backend/app/processors/gf3_water/processor.py

@@ -0,0 +1,14 @@
+"""Backward-compatible processor facade.
+
+New code should import from ``gf3_water.pipeline`` or ``gf3_water.cli``. This
+module remains so existing scripts and integrations that import
+``gf3_water.processor`` continue to work.
+"""
+
+from __future__ import annotations
+
+from .cli import build_arg_parser, main
+from .pipeline import run_from_args
+
+__all__ = ["build_arg_parser", "main", "run_from_args"]
+