docs: clarify remote chonk bench transport

[AztecBot]

Summary

• Clarify that /profile-chonk and /remote-bench build native/WASM bb locally, then copy only binaries and pinned inputs to the bencher.
• Explicitly forbid git bundles, remote worktrees, private GitHub fetches on the bencher, and per-session WASI SDK/toolchain installs on the shared bencher.
• Tell agents to treat missing local emcc, WASI SDK, or other build tooling as a devbox/copy-base bootstrap gap rather than mutating the bencher.

Validation

• git diff --check
• Verified root AGENTS.md on current next indexes profile-chonk and remote-bench, so Codex can discover the skill paths.
• Verified both skill files contain the no-git-bundle/no-remote-worktree/no-per-session-WASI contract.

This is a docs-only correction for the canonical profiling workflow.