[codex] Use close price outside market hours

[aiSynergy37]

Summary

• Make SecurityHolding.TotalCloseProfit() use bid/ask only while regular market hours are open
• Use the security last price outside regular market hours so stale bid/ask quotes do not distort close profit
• Add long and short regression coverage for open vs closed regular market hours

Issue

Fixes #8878

Testing

• dotnet build Tests/QuantConnect.Tests.csproj --no-restore --nologo -v:q -clp:ErrorsOnly -p:RunAnalyzers=false -m:1 -p:UseSharedCompilation=false
• Attempted focused test with Debug project output, but local NUnit discovery returned no matching tests for the new methods in this environment.
• Attempted Release test project build; local build timed out before completion.