Rename root, api and sdk module paths (imports, go.mod, go_package,
ldflags, build scripts, buf configs) and regenerate protobuf/gateway
code with the project's pinned toolchain. Wire identifiers unchanged.
api gets a local replace for sdk; root/api/sdk require v0.1.0.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>