Phase 545: whiteboard Cookbook and screenshot proof route gate

[ExplodingUFO]

Summary

• record the Phase 545 whiteboard Cookbook and screenshot proof route gate in both parity roadmap locales
• add WHITEBOARD_COOKBOOK_SCREENSHOT_PROOF_ROUTE_GATE coverage for future route, shell-state, screenshot metadata, before/after visual evidence, and non-overlap requirements
• keep the slice docs/tests-only with no screenshot manifest, runtime UI, renderer, persistence/schema, or pointer coordinator changes

Verification

• dotnet test tests\AsterGraph.Demo.Tests\AsterGraph.Demo.Tests.csproj -c Release --filter "FullyQualifiedName~ReactFlowParityRoadmapDocsTests.ParityRoadmapDocs_RecordPhase545WhiteboardCookbookScreenshotProofRouteGateInBothLocales" --verbosity minimal
• dotnet test tests\AsterGraph.Demo.Tests\AsterGraph.Demo.Tests.csproj -c Release --filter "FullyQualifiedName~ReactFlowParityRoadmapDocsTests" --verbosity minimal
• dotnet test tests\AsterGraph.Demo.Tests\AsterGraph.Demo.Tests.csproj -c Release --verbosity minimal
• git diff --check (LF-to-CRLF warnings only)

Closes #209