Remote install send a %commit because they receive new files. Local
installs never receive files, so weren't notifying kiln subscribers.
Here we "manually" send a %commit fact when installing a local desk.
Notably, we include the base desk last. This is to ensure that the
other desks are present by the time kiln gets loaded from base, letting
it install the software on the other desks, as per 22ad2516c.
During kiln's +on-init, we now check for non-base (and non-kids) desks.
If any are present, we execute the install flow for them, and set them
to sync from our sponsor afterwards.
This depends on work done in d7afe3229, in that without those changes
the successive +find requests from kiln to clay would clobber each
other, leaving only the "install from sponsor" one active, thus never
actually installing the desk for which we already have the files.
When installing from an existing local desk, kiln now scries the
relevant data out of clay instead of sending moves to it and awaiting
responses.
This prepares for coming kiln work.
If a remote commit is downloaded that simultaneously removes an agent from
desk.bill but also removes the associated source files, then the commit
will fail as gall will not have received the card to kill the agent yet.
Instead, we read our foreign copy of the bill in +take-download, and
kill any necessary agents there, preventing a reload of the deleted
agent from occurring.
When we receive the %mere gift from clay, the kernel has not yet been
reloaded. This means any attempts to bump desks will fail, as they will
be bumped against the old kernel. Rectifies this by continuing the %base
desk update flow in +on-load, instead of +take-merge-main. Also adds a
wef=(unit weft) to the state in order to discriminate whether or not the
kernel has just been reloaded
