Go analysis silently returned zero findings on every platform but Intel
Macs. The shipped Go analyzer was a single darwin/amd64 binary, so Apple
Silicon, Linux, and Windows (including all Linux/Windows CI) skipped Go
entirely and reported a clean tree.

- Ship five static CGO_ENABLED=0 binaries (darwin arm64/amd64, linux
  amd64/arm64, windows amd64) and select the binary from Node's
  platform/arch, not the Go toolchain's (matters under Rosetta where go
  env reports amd64 while Node reports arm64).
- Build the fallback analyzer into the OS cache dir instead of writing
  into the read-only shipped tree and overwriting the artifact.
- Surface a missing toolchain, wrong-arch binary, or failed build as a
  named "Skipped analyzers" diagnostic in the text CLI instead of a
  silent zero.
- Guard 8 now asserts all five shipped binaries are present and that the
  running platform's binary executes.

Remove the superseded single binary and the stale analyzer-src/analyzer-binary
and analyzer-src/main blobs.

Co-Authored-By: Claude <noreply@anthropic.com>