Brainerd Init

Initialize Brainerd in the current repo and route to the correct harness-specific setup path.

Detect the harness first

1. If the active session exposes Pi Brainerd tools, or you are in Pi, use the guarded /brainerd-init command surface. Do not use the shell wrappers in that branch.
2. If CODEX_THREAD_ID is present, use the Codex wrapper:

./scripts/brainerd-codex.sh init

3. If BRAINERD_CLAUDE_SESSION_ID or BRAINERD_CLAUDE_TRANSCRIPT_PATH is present, use the Claude wrapper:

./scripts/brainerd-claude.sh init