test(assets): atlas determinism smoke test (#847)

Adds tests/run-atlas-determinism — imports generate_atlas as a module
and calls process_body() twice with seed=42 and dry_run=True, comparing
the returned markers dicts as JSON. No wiki files are written.

Guardrail against determinism regressions in terrain analysis, city
placement, A* road routing, infrastructure MST, and gate terminal
placement. GJ892f (domed, population 300, 1 city) is the smallest
well-exercised case.

Makefile target: make test-atlas-determinism.
Wired into tests/run-all alongside run-ipc-integration and run-visual.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Makefile

@@ -58,6 +58,7 @@ help:
 	@echo "  make check-star-map    Assert star_map_data.json is up to date (part of pre-pr-client)"
 	@echo "  make economy-db        Import economics data into systems.db (TOML/JSON → SQLite)"
 	@echo "  make atlas-generate    Generate atlas city/road/rail markers for all inhabited bodies"
+	@echo "  make test-atlas-determinism  Determinism smoke test for generate_atlas.py (#847)"
 	@echo "  make fixtures-client    Generate GDScript->Rust cross-encoder fixtures (#475)"
 	@echo "  make golden-diff        Show diff if golden file output has changed"
 	@echo "  make golden-update      Regenerate golden file and stage for commit"
@@ -223,6 +224,9 @@ test-ipc-integration:
 test-ipc-benchmark:
 	tests/run-ipc-benchmark
 
+test-atlas-determinism:  ## Determinism smoke test for generate_atlas.py (#847)
+	tests/run-atlas-determinism
+
 # --- Clean ---
 
 clean-imports: