Calculations are put in 05-onchain.md, and referred to by 02-peer-protocol.

The number is 600, comfortably under the 626 theoretical limit.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

bolt-simple-taproot: make funding symmetric, add new type for shutdown

We add more test vectors to describe how reconnection should be handled after
a splice, before receiving `splice_locked`, when there are pending updates.