Phase 535: refresh post-lasso parity queue

[ExplodingUFO]

Summary

• Record Phase 535 as the post-Phase-534 parity queue refresh in EN/ZH roadmap docs.
• Replace the stale Phase 534 current issue-wave row with Phase 536-540 follow-up candidates for lasso screenshot, toolbar UX, eraser, drawing primitives, and whiteboard persistence/render readiness.
• Add focused docs tests for the Phase 535 tracker references, stale-row removal, scope boundaries, and candidate split.

Verification

• dotnet restore AsterGraph.sln
• dotnet test tests\AsterGraph.Demo.Tests\AsterGraph.Demo.Tests.csproj --filter FullyQualifiedName~ReactFlowParityRoadmapDocsTests --no-restore --verbosity minimal (35 passed)
• git diff --check (line-ending warnings only)
• dotnet build AsterGraph.sln -c Release --no-restore --verbosity minimal (0 warnings, 0 errors)

Closes #193