feat: Advisory hook for architect cd into builder worktrees

[waleedkadous]

When using the architect role, cd-ing into builder worktrees violates the operational rules (should use absolute paths / Read tool instead).

Consider adding an advisory (non-blocking) hook that warns the architect when they attempt to cd into .builders/. The hook should only fire for architect sessions, not builder sessions (builders are already inside worktrees).

Sketch:

# Only warn if we're NOT already in a builder worktree
if [[ "$PWD" != */.builders/* ]] && echo "$CLAUDE_COMMAND" | grep -q '\.builders/'; then
  echo "⚠ Architect: use absolute paths with Read instead of cd-ing into builder worktrees"
fi
exit 0  # advisory, never blocks

Context: came up during ci-channel development when the architect cd'd into a builder worktree to check a diff.