Add ssd_hc.tibble() which can take individual estimates with bootstrap samples and implement all methods except the multis.

Just by using the weights and samples.

Much more efficient for simulations.

Start by locating the ssd_hc.tibble() entry point and reviewing how individual estimates, weights, and bootstrap samples are represented. Done means the new tibble-based interface supports the requested methods, while multis methods remain excluded, and simulations can use weights and samples more efficiently.

Written by the indexing model from the issue text.