Admit captured property update and delete bytecode

[rogeralsing]

Summary

• admit captured dynamic-identifier bases for first-boundary named/computed property updates and deletes
• update compiler helper routing so admitted captured property updates emit LoadDynamicIdentifier instead of declining before the general loop
• add eligibility and public invocation route tests for captured arrow/function-expression property update/delete shapes
• refresh the unified bytecode expansion contract for the new captured property mutation surface

Proof

• rtk dotnet test tests/Asynkron.JsEngine.Tests --filter "FullyQualifiedNameEvaluate_NamedPropertyUpdateWithDynamicIdentifierBase_AcceptsWhenDynamicReadsAreAdmitted|FullyQualifiedNameEvaluate_ComputedPropertyUpdateWithDynamicIdentifierBase_AcceptsWhenDynamicReadsAreAdmitted|FullyQualifiedNameEvaluate_NamedPropertyDeleteWithDynamicIdentifierBase_AcceptsWhenDynamicReadsAreAdmitted|FullyQualifiedNameEvaluate_ComputedPropertyDeleteWithDynamicIdentifierBase_AcceptsWhenDynamicReadsAreAdmitted|FullyQualifiedNameArrowFunction_CapturedPropertyUpdateExpression_UsesUnifiedBytecodeProductionFastPath|FullyQualifiedNameFunctionExpression_CapturedPropertyUpdateExpression_UsesUnifiedBytecodeProductionFastPath|FullyQualifiedNameArrowFunction_CapturedComputedPropertyUpdateExpression_UsesUnifiedBytecodeProductionFastPath|FullyQualifiedNameFunctionExpression_CapturedComputedPropertyUpdateExpression_UsesUnifiedBytecodeProductionFastPath|FullyQualifiedNameArrowFunction_CapturedPropertyDeleteExpression_UsesUnifiedBytecodeProductionFastPath|FullyQualifiedNameFunctionExpression_CapturedPropertyDeleteExpression_UsesUnifiedBytecodeProductionFastPath|FullyQualifiedNameArrowFunction_CapturedComputedPropertyDeleteExpression_UsesUnifiedBytecodeProductionFastPath|FullyQualifiedNameFunctionExpression_CapturedComputedPropertyDeleteExpression_UsesUnifiedBytecodeProductionFastPath" — 12 passed
• rtk dotnet test tests/Asynkron.JsEngine.Tests --filter "FullyQualifiedName~UnifiedBytecodeProductionEligibilityTests" — 384 passed
• rtk dotnet test tests/Asynkron.JsEngine.Tests --filter "FullyQualifiedName~UnifiedBytecodeProductionInvocationTests" — 350 passed
• rtk dotnet test tests/Asynkron.JsEngine.Tests --filter "FullyQualifiedName~UnifiedBytecodeProduction" — 776 passed
• rtk dotnet test tests/Asynkron.JsEngine.Tests --filter "FullyQualifiedName~ActivationSemanticsProofPackTests" — 48 passed
• rtk dotnet test tests/Asynkron.JsEngine.Tests --filter "FullyQualifiedNameExpressionProgramCoverageMapTests&FullyQualifiedNameUnifiedBytecodeExpansionContract_ListsRequiredHeadingsAndCurrentEnums" — 1 passed
• rtk dotnet build -c Release — 11 projects, 0 errors, existing nullable warnings
• rtk rg "EvaluateExpression\(|ProfileEvaluateExpression\(" src/Asynkron.JsEngine/Ast/TypedAstEvaluator.ExecutionPlanRunner* — no matches
• rtk ./tools/profile forloop --memory — Total allocated 6.86 MB
• rtk git diff --check

[Copilot]

Pull request overview

Extends the unified bytecode production fast path to admit captured dynamic-identifier bases for first-boundary named/computed property updates and deletes (e.g., () => obj.value++, () => delete obj[key]).

Changes:

• Eligibility: thread allowsDynamicIdentifiers through TryIsFirstBoundaryNamedPropertyDeleteCandidate, TryIsFirstBoundaryComputedPropertyDeleteCandidate, and TryIsFirstBoundaryPropertyUpdateCandidate so dynamic-identifier bases are accepted when admitted.
• Compiler: add TryAppendActivationOrPlainDynamicIdentifierReadValueLoad helper and route the named/computed property update appenders through it (emitting LoadDynamicIdentifier); plumb allowsDynamicIdentifiers into the computed-key span check.
• Tests / docs: new eligibility tests and 8 invocation fast-path tests for arrow + function-expression captured update/delete shapes; expansion contract doc updated for the new admitted surface.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/Asynkron.JsEngine/Execution/UnifiedBytecode/UnifiedBytecodeProductionEligibility.cs	Pass allowsDynamicIdentifiers through update/delete candidate checks.
src/Asynkron.JsEngine/Execution/UnifiedBytecode/UnifiedBytecodeCompiler.cs	New helper for activation-or-dynamic-identifier base load; wired into named/computed property update appenders.
tests/Asynkron.JsEngine.Tests/UnifiedBytecodeProductionEligibilityTests.cs	Added 4 eligibility acceptance tests for dynamic-identifier-base update/delete shapes.
tests/Asynkron.JsEngine.Tests/UnifiedBytecodeProductionInvocationTests.cs	Added 8 fast-path invocation tests covering arrow/function-expression update/delete (named & computed).
docs/unified-bytecode-expansion-contract.md	Update date and decline-code descriptions to reflect newly admitted surface.

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