Add arrow input array support for .many() (#621)

* Initial .many(arrow_array)

* Test with polars/nanoarrow/arro3

* Fix MSRV

* Add arrow pckgs to [test]

* Fix wheel tests

* Revert test_arrow_input.py creation

* Add many(arrow) examples to readme

* Use UPath for s3 example

* Fix readme example

* Do not test polars with free-threading

* Do not test polars with free-threading

* Remove nanoarrow from free-threading

Author: hombit

CHANGELOG.md

@@ -9,7 +9,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
---
+- Arrow input support for `.many()`: pass a `List<Struct<t, m[, sigma]>>` Arrow array (or chunked array)
+  instead of a list of tuples. Works with any library implementing the Arrow C Data Interface
+  (`__arrow_c_array__` / `__arrow_c_stream__`), including pyarrow, polars, nanoarrow, and arro3.
+  Two struct fields means `(t, m)` without sigma, three fields means `(t, m, sigma)`. Field names are
+  ignored; all fields must share the same float dtype (float32 or float64).
 
 ### Changed
 

CLAUDE.md

@@ -80,6 +80,11 @@ periodogram), `gsl`, `mimalloc`. Default features include abi3, ceres-source, gs
 
 **Code style**: Line length 120, Python target 3.10+, Ruff for Python linting (rules: F, E, W, I001, NPY201).
 
+**Rust style**: Write idiomatic Rust — prefer immutability by default (`let` over `let mut`), use iterators and
+combinators (`.map()`, `.filter()`, `.collect()`, `.fold()`, etc.) instead of imperative `for` loops with manual
+accumulation, leverage pattern matching and `if let`/`let else` over nested `if`/`else` chains, use `?` for error
+propagation, and prefer owned types only when necessary (borrow when possible).
+
 ## Adding a New Feature Extractor
 
 1. Core implementation goes in upstream `light-curve-feature` Rust crate