Summary

• detect cloned repositories with repo-local flake.nix during repo instruction discovery
• generate REPO_ENVIRONMENT.md with native nix develop commands for each flake-backed repo
• append a Repository Environments section to workspace AGENTS.md so agents know to use the repo flake for repo-local commands

Notes

• Keeps workspace flake behavior as the global claw/tooling environment.
• Does not introduce a custom helper command; generated guidance uses native nix develop directly.

Tests

• env GOCACHE=/private/tmp/elasticclaw-go-build go test ./pkg/hub
• env GOCACHE=/private/tmp/elasticclaw-go-build go test ./...