docs: scout open JTS PRs + #1212 in-circle differential lane

[grootstebozewolf]

Summary

• Scout all 49 open locationtech/jts PRs against this corpus; risk/cost rank → P0 mesh-first stack headed by jts#1212.
• Session 1 (GREEN) of the mesh in-circle lane: differential harness for INCIRCLE_SIGN + Stage A mirror of TrianglePredicate.isInCircleRobust.

Files

Path	Role
docs/jts-open-prs-scout-2026-08.md	Full 49-PR inventory + picks
docs/jts-1212-incircle-lane-2026-08.md	Session outcome
oracle/gen_jts1212_incircle_vectors.py	Generator / gate
oracle/jts1212_incircle_vectors.txt	29-vector table

Gate (local)

Vectors: 29
EXPECTED pin failures: 0
Stage A CERTAIN vs oracle conflicts: 0
Stage A UNCERTAIN: 11 (correct declines)
Highlight: jts1212_geos955_subset → Stage A ZERO/UNCERTAIN, oracle POS

Test plan

• python oracle/gen_jts1212_incircle_vectors.py with WSL oracle_bin (pin POS 1.5; exit 0)
• Optional: wire as make -C oracle smoke later (not required for merge)

[grootstebozewolf]

Thanks — LGTM taken.

Nits

• make -C oracle smoke stays deferred; merge gate remains python oracle/gen_jts1212_incircle_vectors.py exit 0 (self-check + oracle pin).
• Explicit topic: already on both docs (docs routing + mesh on the lane outcome); no further header churn.

Ready to merge when you are.