chore: bump swiss for Go 1.27 support

[RandyMcMillan]

Update github.com/cockroachdb/swiss to a revision that builds with Go 1.27.
The previous pin gated runtime internals behind !go1.27, which broke make build.
Keep the root module, docs example, and test dependency modules in sync.

[RandyMcMillan]

REF: https://github.com/Homebrew/homebrew-core/blob/main/Aliases/go%401.27
REF: https://github.com/Homebrew/homebrew-core/blob/main/Formula/g/go.rb

[RandyMcMillan]

rebased 000c2b0

if version pinning becomes an issue:

00070cf was passing full tests on MacOS 26.5 (25F71) - go version go1.27.1 darwin/arm64 and Homebrew 6.0.21 prior to rebase

[lidel]

Thanks! Since this is low level dependency, bumping in Kubo is not the best way of doing this, creates divergence across go-based stack.

Kubo tracks pebble through go-ds-pebble, so the bump has to land there first. pebble v2.1.7 is exactly this swiss change.

@gammazero could you bump pebble to v2.1.7 in go-ds-pebble and cut a release? This PR then becomes a go-ds-pebble bump (go get github.com/ipfs/go-ds-pebble@vX.Y.Z && make mod_tidy), which moves pebble and swiss along with it.

[gammazero]

This is handled by #11451