Replace all 27 instances of fmt.Errorf/errors.New in production code
with coreerr.E() from forge.lthn.ai/core/go-log for structured error
context (op, message, cause). Promote go-log from indirect to direct
dependency in go.mod.
Co-Authored-By: Virgil <virgil@lethean.io>
Process management with Core IPC integration, output streaming via
ring buffer, exec wrapper with logging, and dependency-aware runner.
Moved from forge.lthn.ai/core/go/pkg/process to standalone module.
Co-Authored-By: Virgil <virgil@lethean.io>
