add wordbeamsearch to requirements.txt instead of separate build

Author: rvankoert

requirements.txt

@@ -1,3 +1,5 @@
+# requirements.txt
+
 numpy==2.1.3
 editdistance==0.8.1
 tensorflow[and-cuda]==2.19.0
@@ -21,3 +23,12 @@ psutil==7.0.0
 scipy==1.15.3
 vgslify==0.14.0
 python-bidi
+
+# Word beam search decoder (needed by `utils/threading.py`)
+# If no wheel is available for your Python version, pip will build from source.
+word-beam-search @ git+https://github.com/githubharald/CTCWordBeamSearch
+
+# Build helpers (ensure native extensions like word-beam-search compile cleanly)
+setuptools>=65
+wheel
+pybind11