Implement YStripesPointInAreaLocator

[micycle1]

A faster point-in-area locator.

• Uses the technique described here: https://github.com/tidwall/tg/blob/main/docs/POLYGON_INDEXING.md#ystripes
• Faster than IndexedPointInAreaLocator (4x+ in my various tests).
• Passes all AbstractPointInRingTest tests.

It's packaged such that the core polygon algo (YStripesPointInPolygonLocator) is defined in its own non-public class, then the Area variant constructs PolygonLocators for each Polygon in a Geometry, indexed via an STRtree.

The name could be changed too. Of course this too is an indexed PointInAreaLocator, but that exact name is taken.

[grootstebozewolf]

Corpus PIP gallery gate against this PR's Y-stripe algorithm (NetTopologySuite.Proofs).

What we checked

Faithful port of YStripesPointInPolygonLocator / YStripesPointInAreaLocator (DD ray-crossing + Y-stripes) run against the Qed-backed gallery in nts-oracle-gallery.md, side-by-side with NTS 2.6 IndexedPointInAreaLocator and SimplePointInAreaLocator.

Write-up + table: jts-1145-pip-lane (corpus PR #451)
Harness: dotnet run --project tests/Discussion839Mre -c Release -- --jts1145

Results (14/14)

Case	Point	Geometric GT	YStripes
Diamond generic	(0, 0.5)	INTERIOR	INTERIOR
Vertex graze (naive parity even)	(0, 0)	INTERIOR	INTERIOR
Horizontal edge (naive parity odd)	(−1, 1) on notch	EXTERIOR	EXTERIOR
Rect interior / edges	…	INT / BOUNDARY	match
Hot-pixel centre / bottom	…	INT / BOUNDARY	match
Spectre interior / reflex pocket	(5, 0.5) / (3.5, 0.5)	INT / EXT	match
Hat interior / pocket (√3 APPROX WKT)	…	INT / EXT	match

Also bit-equal to Indexed and Simple on every row (no locator split).

Suggestion

AbstractPointInRingTest already covers comb / repeated pts / a few robust triangles. Adding the gallery WKT pins (especially diamond graze, horizontal-edge exterior, Spectre pocket) would lock both this locator and IndexedPointInAreaLocator against the classes that pure half-open ray parity gets wrong without special cases.

No objection on soundness from this corpus gate. Port risk residual: Java tip not executed under JVM here (C# line-faithful port + NTS CGAlgorithmsDD).

(Affiliation: NetTopologySuite.Proofs — formal companion, not a JTS committer review.)