Embed missing System.Text.Json transitive dependencies in PerfView

[brianrob]

Summary

The self-extracting PerfView EXE is missing two transitive dependencies of System.Text.Json 9.0.8:

• System.IO.Pipelines.dll
• Microsoft.Bcl.AsyncInterfaces.dll

Without these DLLs, System.Text.Json silently fails when parsing ProcessMappingMetadata.SymbolMetadata JSON strings during nettrace-to-ETLX conversion. This causes ParsedSymbolMetadata to return null, so MatchOrInitElf()/MatchOrInitPE() are never called, symbolInfo stays null, and BinaryFormat returns Unknown — breaking ELF symbol resolution for Linux .nettrace traces.

Root Cause

PerfView embeds DLLs as EmbeddedResource items in PerfView.csproj. System.Text.Json and its direct dependency System.Text.Encodings.Web were already embedded, but the transitive dependencies System.IO.Pipelines and Microsoft.Bcl.AsyncInterfaces were not. Local builds work because the output directory contains all transitive NuGet dependencies, but the official self-extracting EXE only includes explicitly listed resources.

Verification

Configuration	ELF Modules	PE Modules
Official 3.2.0 (missing deps)	0	0
Official + 2 missing DLLs added	83	34
Local build (all deps present)	83	34

Changes

• src/Directory.Packages.props: Added System.IO.Pipelines and Microsoft.Bcl.AsyncInterfaces v9.0.8
• src/PerfView/PerfView.csproj: Added PackageReference with GeneratePathProperty="true" and EmbeddedResource entries for both DLLs

Testing

• Full build succeeds
• All 4565 TraceEvent tests pass (2271 net8.0 + 2288 net462 + 6 skipped)
• Standalone ETLX conversion test confirms correct module binary format detection
• End-to-end validation: isolated self-extracting PerfView.exe correctly extracts both DLLs and produces ETLX with 166 ElfSymbolInfo + 68 PESymbolInfo objects