feat: side-input for pynumaflow-lite

[vigith]

Closes #292

(pynumaflow-lite) ➜  pynumaflow-lite git:(side-input) ✗ make test
maturin develop
🍹 Building a mixed python/rust project
🔗 Found pyo3 bindings
🐍 Found CPython 3.13 at /Users/vigith/code/git/numaproj/numaflow-python/packages/pynumaflow-lite/.venv/bin/python
📡 Using build options features from pyproject.toml
   Compiling numaflow v0.4.0 (https://github.com/numaproj/numaflow-rs.git?rev=44ee3068fcf7088ff265df7ae7ce1881a40694ff#44ee3068)
   Compiling pynumaflow-lite v0.1.0 (/Users/vigith/code/git/numaproj/numaflow-python/packages/pynumaflow-lite)
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 11.03s
📦 Built wheel for CPython 3.13 to /var/folders/9v/ztc8jgrn1b9dvwd5sv1z0ndh0000gp/T/.tmpTnKNCk/pynumaflow_lite-0.1.0-cp313-cp313-macosx_11_0_arm64.whl
✏️ Setting installed package as editable
🛠 Installed pynumaflow-lite-0.1.0
pytest -v
================================================================================================= test session starts =================================================================================================
platform darwin -- Python 3.13.2, pytest-8.4.2, pluggy-1.6.0 -- /Users/vigith/code/git/numaproj/numaflow-python/packages/pynumaflow-lite/.venv/bin/python3
cachedir: .pytest_cache
rootdir: /Users/vigith/code/git/numaproj/numaflow-python/packages/pynumaflow-lite
configfile: pyproject.toml
collected 16 items

tests/test_accumulator.py::test_python_accumulator_server_and_rust_client[accumulator_stream_sorter.py] PASSED                                                                                                  [  6%]
tests/test_batchmap.py::test_python_batch_server_and_rust_client[batchmap_cat.py] PASSED                                                                                                                        [ 12%]
tests/test_batchmap.py::test_python_batch_server_and_rust_client[batchmap_cat_class.py] PASSED                                                                                                                  [ 18%]
tests/test_map.py::test_python_server_and_rust_client[map_cat.py] PASSED                                                                                                                                        [ 25%]
tests/test_map.py::test_python_server_and_rust_client[map_cat_class.py] PASSED                                                                                                                                  [ 31%]
tests/test_mapstream.py::test_python_stream_server_and_rust_client[mapstream_cat.py] PASSED                                                                                                                     [ 37%]
tests/test_mapstream.py::test_python_stream_server_and_rust_client[mapstream_cat_class.py] PASSED                                                                                                               [ 43%]
tests/test_reduce.py::test_python_reduce_server_and_rust_client[reduce_counter_class.py] PASSED                                                                                                                 [ 50%]
tests/test_reduce.py::test_python_reduce_server_and_rust_client[reduce_counter_func.py] PASSED                                                                                                                  [ 56%]
tests/test_reducestream.py::test_python_reducestream_server_and_rust_client[reducestream_counter.py] PASSED                                                                                                     [ 62%]
tests/test_session_reduce.py::test_python_session_reduce_server_and_rust_client[session_reduce_counter_class.py] PASSED                                                                                         [ 68%]
tests/test_sideinput.py::test_python_server_and_rust_client[sideinput_example.py] PASSED                                                                                                                        [ 75%]
tests/test_sink.py::test_python_sink_server_and_rust_client[sink_log.py] PASSED                                                                                                                                 [ 81%]
tests/test_sink.py::test_python_sink_server_and_rust_client[sink_log_class.py] PASSED                                                                                                                           [ 87%]
tests/test_source.py::test_python_source_server_and_rust_client[source_simple.py] PASSED                                                                                                                        [ 93%]
tests/test_sourcetransform.py::test_python_server_and_rust_client[sourcetransform_event_filter.py] PASSED                                                                                                       [100%]

================================================================================================= 16 passed in 33.25s =================================================================================================
(pynumaflow-lite) ➜  pynumaflow-lite git:(side-input) ✗

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.88%. Comparing base (41f6c0f) to head (4ffdfac).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #296      +/-   ##
==========================================
+ Coverage   93.85%   93.88%   +0.03%     
==========================================
  Files          66       66              
  Lines        3009     3009              
  Branches      155      155              
==========================================
+ Hits         2824     2825       +1     
+ Misses        135      134       -1     
  Partials       50       50              

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