Fix import planning order for action-scoped variables

Summary

• Reordered Octopus import planning so deployment processes, steps, and actions are created before project variable sets, ensuring action destination IDs exist before scope mapping.
• Synchronized OctopusImportPreviewPlanner ordering and added unit coverage to prevent dependency and preview rank drift.
• Extended the real archive integration scenario with Action and Process-scoped variables, verifying persisted scope values against the actual destination IDs.
• Updated OCTOPUS_IMPORT_API_REVIEW_MEMORY.md with the C8 resolution, rationale, modified files, verification results, and remaining machine/tenant product-scope limitations.

Test plan

• Squid.UnitTests Release build completed with 0 errors.
• Squid.IntegrationTests Release build completed with 0 errors.
• git diff --check passed.