Step NC05: Chat Provider SPI And Foundations

[deku2026]

Summary

• Implements Step NC05: Chat Provider SPI And Foundations
• Keeps scope limited to the active step
• Updates traceability and acceptance evidence required by the step
• Lands the chat-provider SPI, registry decorators, tokenizer bundle, OpenAI, Anthropic, Google, and GenericOpenAI providers, plus desktop provider selection wiring.

Verification

• dotnet test apps/desktop/ArcChat.Desktop.UiTests/ArcChat.Desktop.UiTests.csproj -m:1 /p:TreatWarningsAsErrors=true: passed, 46 tests
• dotnet test packages/local-services/ArcChat.LocalServices.Tests/ArcChat.LocalServices.Tests.csproj -m:1 /p:TreatWarningsAsErrors=true: passed, 4 tests
• dotnet test tests/ArcChat.Architecture.Tests/ArcChat.Architecture.Tests.csproj -m:1 /p:TreatWarningsAsErrors=true: passed, 15 tests
• dotnet format ArcChat.slnx --verify-no-changes --no-restore --verbosity minimal: passed
• git commit -m "feat(provider): Step NC05 closure - Wire desktop provider selection": pre-commit hook passed tool build, format, solution build, and full test run

Traceability

• Rows updated: NC-PROV-001, NC-PROV-002, NC-PROV-003, NC-PROV-004
• Matrices updated: provider-parity-matrix.md, traceability-matrix.md, settings-schema-migration-matrix.md, docs/coverage/settings-schema.md, docs/coverage/providers-live-demo.md
• Final-gate impact: FG.06 provider contract coverage and desktop provider resolution now have NC05 evidence; FG.08 provider defaults evidence updated

Out Of Scope

• NC06 provider wave providers beyond the required NC05 reference providers
• OpenAI image generation, which remains NC13.03 behind IImageGenProvider
• OS keychain settings migration and API-key UI, which remain NC15.08
• Live provider execution without developer-supplied API keys

Open Questions

• None