Replace fmt, errors, strings, path/filepath, encoding/json with Core
primitives across 23 files. Keep encoding/json for streaming
NewDecoder/NewEncoder, strings for Fields/FieldsFuncSeq.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Update Go module path from forge.lthn.ai/core/go-forge to
dappco.re/go/core/forge. Migrate all import paths and dependency
references (go-io → dappco.re/go/core/io, go-log → dappco.re/go/core/log).
Update documentation (CLAUDE.md, README.md, docs/) to reflect new paths.
Co-Authored-By: Virgil <virgil@lethean.io>