perf(python): rewrite hot Seq combinators as native Python generators

[MangelMaxime]

Python's Seq combinators built on generate/Enumerator.generateWhileSome: an Option allocated per element, plus a MoveNext/Current call per step - a faithful port of F#'s IEnumerable/IEnumerator model, but on CPython the per-element object churn dominates.

Benchmark

Compiled a pipeline exercising several of the converted combinators together (map, choose,
map2, takeWhile, tryItem, fold - not just map/filter/collect), before vs after,
5,000 calls:

before	after	speedup
4.60s	2.91s	1.58x

Results identical both runs: 69360.

A simpler map/filter/collect/fold pipeline measured separately shows ~1.7x.

[github-actions]

Python Type Checking Results (Pyright)

Metric	Value
Total errors	34
Files with errors	4
Excluded files	4
New errors	✅ No

Excluded files with errors (4 files)

These files have known type errors and are excluded from CI. Remove from pyrightconfig.ci.json as errors are fixed.

File	Errors	Status
temp/tests/Python/test_hash_set.py	18	Excluded
temp/tests/Python/test_applicative.py	12	Excluded
temp/tests/Python/test_nested_and_recursive_pattern.py	2	Excluded
temp/tests/Python/fable_modules/thoth_json_python/encode.py	2	Excluded