RxPY v5 (#743)

* Add back fluent method chaining

* Add windowing operators

* Add more tests

* Formatting

* Update deps

* Update docs

* Curry flip

* Use curry-flipping operators

* Better generic types

* Format test files with ruff

Apply ruff formatting to all test files as Stage 0 of the test linting
enablement plan. This separates formatting changes from type annotation
work for cleaner diffs and easier review.

Changes:
- 19 files reformatted (mainly removing unnecessary line breaks)
- 167 files already formatted (no changes)
- All tests still pass

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

* Update ruff configuration for staged test linting

Replace blanket "tests" exclusion with specific directory exclusions
matching the pyright configuration. This aligns both tools and makes
the staged rollout plan clearer.

Changes:
- Remove generic "tests" from ruff exclude list
- Add specific test directories to exclude
- Both ruff and pyright now have identical test exclusions
- Will remove exclusions incrementally as each stage completes

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: dbrattli

README.rst

@@ -1,6 +1,6 @@
-===============================
 The ReactiveX for Python (RxPY)
 ===============================
+===============================
 
 .. image:: https://github.com/ReactiveX/RxPY/workflows/Python%20package/badge.svg
     :target: https://github.com/ReactiveX/RxPY/actions
@@ -59,6 +59,43 @@ Schedulers.
     composed.subscribe(lambda value: print("Received {0}".format(value)))
 
 
+Fluent and Functional Syntax
+-----------------------------
+
+RxPY supports both **fluent** (method chaining) and **functional** (pipe-based) syntax,
+giving you the flexibility to choose the style that works best for your codebase:
+
+**Fluent style** - Method chaining for a more Pythonic feel:
+
+.. code:: python
+
+    import reactivex as rx
+
+    result = (rx.of(1, 2, 3, 4, 5)
+        .map(lambda x: x * 2)
+        .filter(lambda x: x > 5)
+        .reduce(lambda acc, x: acc + x, 0)
+    )
+    result.subscribe(print)  # Output: 24
+
+**Functional style** - Pipe-based for functional composition:
+
+.. code:: python
+
+    import reactivex as rx
+    from reactivex import operators as ops
+
+    result = rx.of(1, 2, 3, 4, 5).pipe(
+        ops.map(lambda x: x * 2),
+        ops.filter(lambda x: x > 5),
+        ops.reduce(lambda acc, x: acc + x, 0)
+    )
+    result.subscribe(print)  # Output: 24
+
+Both styles are **fully supported** and can even be mixed in the same pipeline.
+Choose the style that best fits your team's preferences and coding standards.
+
+
 Learning ReactiveX
 ------------------
 
@@ -106,8 +143,12 @@ need to be written with an ``_`` in Python:
 
 .. code:: python
 
+    # Functional style
     group = source.pipe(ops.group_by(lambda i: i % 3))
 
+    # Or fluent style
+    group = source.group_by(lambda i: i % 3)
+
 With ReactiveX for Python you should use `named keyword arguments
 <https://docs.python.org/3/glossary.html>`_ instead of positional arguments when an
 operator has multiple optional arguments. RxPY will not try to detect which arguments
@@ -116,34 +157,30 @@ you are giving to the operator (or not).
 Development
 -----------
 
-This project is managed using `Poetry <https://python-poetry.org/>`_. Code is formatted
-using `Black <https://github.com/psf/black>`_, `isort
-<https://github.com/PyCQA/isort>`_. Code is statically type checked using `pyright
-<https://github.com/microsoft/pyright>`_ and `mypy <http://mypy-lang.org/>`_.
+This project is managed using `uv <https://docs.astral.sh/uv/>`_. Code is formatted
+using `Ruff <https://github.com/astral-sh/ruff>`_. Code is statically type checked
+using `pyright <https://github.com/microsoft/pyright>`_.
 
-If you want to take advantage of the default VSCode integration, then
-first configure Poetry to make its virtual environment in the
-repository:
+After cloning the repository, install dependencies:
 
 .. code:: console
 
-    poetry config virtualenvs.in-project true
+    uv sync
 
-After cloning the repository, activate the tooling:
+Run unit tests:
 
 .. code:: console
 
-    poetry install
-    poetry run pre-commit install
+    uv run pytest
 
-Run unit tests:
+Run type checking:
 
 .. code:: console
 
-    poetry run pytest
+    uv run pyright
 
 Run code checks (manually):
 
 .. code:: console
 
-    poetry run pre-commit run --all-files
+    uv run pre-commit run --all-files