Implements tasks for creating and deleting new sessions, and allows
terminal handler agents to distinguish between sessions.
Includes bits of preparation in drum to more fully support multiple
distinct sessions, but doesn't get it all the way there just yet.
Gall would send %onto gifts to notify about app updates and update
failures. This would end up in dill, which printed some appropriate
text.
Here, we make gall responsible for doing this printing itself (by
having it explicitly ask dill to print some tape/tank), instead of
relying on the receiving end of some bespoke notification protocol.
This comes with the caveat that this specific mouse reporting mode
(which should only report clicks of the primary button) doesn't
actually seem to be supported by most terminal emulators, even though
it precedes the more complex reporting modes.
(Enabling a more complex reporting mode instead would also capture
scroll events, which interferes with expected behavior while in tmux.)
New blit logic already stopped assuming the bottom line based on %nel
blits, instead looking at cursor position to determine if something
was getting drawn to the bottom of the screen or not.
Here, we stop overwriting the bottom line entirely (except for the
spinner), instead inserting the trace/slog directly above the bottom
line on-screen, without overwriting anything.
Side-effect of this is that trailing newlines are always there, so we
can stop including them explicitly.
Separately from deriveNoun, which gives you an entire instance. Having
access to these lets you call out to the auto-generated conversion
logic when writing custom code for it.
The previous version allowed for redundant values (both [%bac ~] and
[%key ~ %bac ~] for example), had an odd constraint in @cF, and relied
unnecessarily on $<.
Also rewords some of the belt and blit descriptions.
Results in slightly better behavior... but it still breaks on dev
auto-refresh?
Also no longer does the ''<->'default' transform for the default session
identification in state, instead always using the empty string.
Previously, we relied on foolish hacks, like [%met %bac], to send
"special" keystrokes with modifiers.
This updates the belt type to have %key, which represents a single
keystroke, with any combination of modifier keys.
Note that this has overlap with %txt to some extent. [%key ~ 'a'] should
be considered equivalent and preferred to [%txt 'a' ~], but updating
existing usage is left to a later commit.
