v0.3.6 — a repo says where its worktrees live

• wave repos add <path> --worktree-prefix ~/kyte-worktrees/demeter-: worktrees follow the repo's own convention instead of ../<repo>-<N>; ~ is expanded, relative prefixes resolve against the checkout.
• Registry entries for two repos with a non-default layout were the motivating case; wave facts on both read gate: <no gate found> — the evidence behind #3, #15 and #17 in the v0.4.0 epic.