chore: migrate to dappco.re vanity import path
Module path: forge.lthn.ai/core/go-ai -> dappco.re/go/core/ai
Updated all .go imports for migrated sibling packages:
- forge.lthn.ai/core/go-log -> dappco.re/go/core/log
- forge.lthn.ai/core/go-io -> dappco.re/go/core/io
- forge.lthn.ai/core/go-i18n -> dappco.re/go/core/i18n
Added //go:build ignore to cmd/lab/cmd_lab.go (pre-existing broken
import: forge.lthn.ai/lthn/lem/pkg/lab was removed from LEM).
Packages not yet migrated (left as-is): cli, go-rag, go-scm,
go-process, mcp, api, go-crypt, go-inference, go-ml, go-mlx.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>