focus history is a stack of locations, and the Jumplist is that same stack

One container, not two: focus_hist (a stack of pane ids rebuilt every sync) is
now jumps[] + a current pointer, and the +Jumps buffer is a RENDERING of that
array — nothing copies it, nothing shadows it. prevFocus, Toggleterm, Look's
directory order, Back/Forward, Last and Jumplist all walk the one list.

A pane id is reused, so a location that only remembered an id would retarget
after a respawn: panes now carry a monotonic serial and an entry whose slot
holds a different serial is dead. trackJump compacts those out and fixes the
pointer in the same pass.

The push rule lives in ONE place and says: a location is worth remembering
when you cannot see it any more — a different pane, or more than a bodyful of
rows away in the same one. So hjkl never grows the list and 100G, a search hit
and a goto-definition do.

Ctrl-o/Ctrl-i walk it, SPC j j toggles the last two, SPC j l lists them.
Ctrl-i IS Tab on a legacy host, where the binding simply never fires and
Tab-executes is untouched; kitty reports them apart. SPC j o/i work anywhere.

Two goldens moved, both the SPC ? Help listing gaining four rows.

1 files changed, 1 insertions, 1 deletions

diff --git a/next-steps.txt b/next-steps.txt
index 29073998..a230beca 100644
--- a/next-steps.txt
+++ b/next-steps.txt
@@ -9,5 +9,5 @@
 - There's some bug when rendering from a ssh session - the screen gets dirty with old chars when scrolling.
 - There's some bad performance when dealing with specially large files or long lines; write a perf harness for this and optimize the performance.
 + The Look and Exec should be regular semantic entities, i.e. their only special feature should be the keys/shortcuts they're assigned so we could execute Look main.zig and it would call the regular look on it, but also we could Look some string like @`ls -la` (you can change the syntax, but this also depends on that syntax change so it's centralized and easy to change later). This basically will allow you to make some big refactorings and cut a lot of code (hopefully) and also allow some funny things like @`Look .` (basically allowing nested things like this for no good reason other than, it's elegant and it's fun!) 
-- We'll make the focus history a meaningful and strong semantic entity: instead of being a stack of Panes, it'll be a stack of locations. This will allow us to implement vim's ctrl-i and ctrl-o that will just move the current focus up or down on that stack. there'll be also a new builtin that will toggle the focus of the latest panes, basically moving the current focus by changing the current pointer to the location on the stack. The Jumplist (new builtin) will be an Output pane with each line being a location that can be Looked, n/N should work.
++ We'll make the focus history a meaningful and strong semantic entity: instead of being a stack of Panes, it'll be a stack of locations. This will allow us to implement vim's ctrl-i and ctrl-o that will just move the current focus up or down on that stack. there'll be also a new builtin that will toggle the focus of the latest panes, basically moving the current focus by changing the current pointer to the location on the stack. The Jumplist (new builtin) will be an Output pane with each line being a location that can be Looked, n/N should work.
 + The main pardes.zig file should hold the logic that applies to all kinds of panes and backends. Maybe right now the pane specifiticies are too intermingled. Maintain the panes logics into their own files, right now tty.zig exists but I don't think output panes live by themselves nor file panes on their own files. Also, each builtin command should be implemented as a struct, the current logic on switching on the enum should use some comptime logic to build the tagged union/enum from those structs now. Also I think it's time to create a few directories on @src now since some files are specific to some backends and others are part of the core, it should be clear just by looking at the directory structure (don't add more dir layers, just new  dirs under src).