Move extension methods onto typed query registry

[richlander]

Moves extension-method inspection from the string-keyed ScannerRegistry onto the shared typed query registry. ExtensionMethodsQuery returns immutable L1 currency; Library Info and Extension Methods bind to the same query definition, and the CLI adds Finding provenance and compatibility projections after execution.

This preserves Markdown/JSON output, presence-based discovery, typed failures, the shared metadata session, and NativeAOT behavior. Other scanner-backed facets remain unchanged.

Validation:

• dotnet build dotnet-inspect.slnx -c Release
• source eng/activate-iltools.sh --mdv && dotnet run --project src/dotnet-inspect.Tests -c Release --no-build -- -class DotnetInspector.Tests.SectionPipelineTests -class DotnetInspector.Tests.LibraryFindingConsumerTests
• Full CLI suite in Release with the known concurrent timing canary excluded; the canary passes alone
• NativeAOT publish plus a real Extension Methods JSON probe
• markdownlint on changed documentation

[richlander]

Fixed-head adversarial review completed at 451a295a03926f0eff46dbe96bbcd0b2d2b32f1d against 0ff89befc5c822bbba863b8bdbd75d2447ca7d3b.

• GPT-5.6 Sol: clean. Verified typed demand identity and single execution, failure/Finding projection, borrowed-session lifetime, native/no-metadata behavior, package/discovery routes, output parity, layering, and documentation boundaries.
• Claude Opus 5: clean. Independently verified the same production paths, ran base/head parity probes across CLI formats and package routes, and mutation-checked that the shared Library Info/Extension Methods binding is covered by production-wiring tests.

No findings required action. Current-head ci-required is green and the PR is mergeable.

Ready to merge.

[richlander]

Conflict-resolution review completed at 952deb246efe61b0a972447fb9653130cbe72a2c against 1d47eb9443d6bf00d8546a5da90277001441467a.

• GPT-5.6 Sol: clean. Verified mixed synchronous/asynchronous query execution, complete registration and result projection, shared extension demand, no incidental SourceLink acquisition, exact-section behavior, and documentation boundaries.
• Claude Opus 5: clean. Independently exercised the composed extension/SourceLink registry, full CLI and query suites, native and corrupt inputs, and byte-for-byte base/head parity across library, package, discovery, and structured-output routes.

No findings required action. Current-head ci-required is green, main is fully integrated, and the PR is mergeable.

Ready to merge.

[richlander]

Workspace/query conflict-resolution review completed at f115911cc040bc1c1a29bf5dada893430cf6b883 against 945e7502fa03254e7b1c3fc55113cc42dfb560df.

• GPT-5.6 Sol: clean. Verified single-library/group-query partitioning, retained-image lifetime, extension-query single execution, multi-assembly rendering, failures, costs, and documentation.
• Claude Opus 5: clean. Independently exercised combined @Integrations/Extension Methods routes, native and multi-assembly cases, base/head parity, and mutation-checked the shared Library Info binding.

No findings required action. Current-head ci-required is green after an unchanged-head retry of the unrelated Windows package-publication concurrency flake; main is fully integrated and the PR is mergeable.

Ready to merge.