Undoes the go.mod/setup-go pin to 1.25 from the previous commit. The maintainer requires Go 1.26. The TinyGo net/http wasm build failure is an upstream toolchain bug (tinygo-org/tinygo#5467) and is being resolved separately without changing the Go version. Not pushed pending the toolchain-fix decision (issue #26). Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>