Kris Nuttycombe

Returning to draft status to update the parsing of the HRP for ZIP 316, Revision 1

[force-pushed](https://github.com/zcash/librustzcash/compare/7bace95cabb48f03ba864489d220cb757bdfefb9..3742501615b8729db64848539e0ccd9cd76cca2d) to fix conflicts with `main`.

[force-pushed](https://github.com/zcash/librustzcash/compare/7852a319e69e4c291ea63e7c19b66d48f905b398..f1455af54ff10bb1e0f7ba4ef9bd27adfd3fa0c3) to address comments from code review.

[force-pushed](https://github.com/zcash/librustzcash/compare/38cb9466aa00df8a2670782dbc447c7261ab9496..014e992bbfa955c940e12f0e9a1d2d5136c165a4) to rebase on `main` & fix conflicts with `no_std` changes. Then [force-pushed](https://github.com/zcash/librustzcash/compare/014e992bbfa955c940e12f0e9a1d2d5136c165a4..154b0021292046782bc96640c934a161f7407708) to take into account review suggestions.

An additional report of this issue was made here: https://discord.com/channels/809218587167293450/809251012610752513/1280161414102913075 Details on the forum: https://forum.zcashcommunity.com/t/nu6-testnet-activation-height-has-been-set/48646/26

Additional report: https://forum.zcashcommunity.com/t/nu6-testnet-activation-height-has-been-set/48646/20

Supplanted by #1923

Also consider the remaining comments on #1306 when implementing these changes.

> Overall I think 2 is better. It's definitely closer to being normalized: for approach 1 there ends up being a lot of duplicated information in `sent_notes`. I tend to...

> Is there any ZIP that forbids or strongly discourages funding across accounts? If so, that would be good grounds to not support it. We should definitely recommend against it...