slosh: split app.c into five units, mechanically

app.c was 7k lines wearing section markers; now the markers are files,
cut exactly along them, no behaviour change:

  app.c          the session core: config in force, pane and tab
                 lifecycle, walking, input routing, introspection
  app_layout.c   layout, tree edits, resizing, equalising, rotating,
                 focus
  app_session.c  layout files, checking, workspaces, dumping a session
  app_draw.c     drawing, the shader passes, kitty graphics
  app_ui.c       the finder, modals, the palette, the project picker,
                 renaming

include/app_internal.h carries what the five share: the tree/tab/app
structs, CFG and the palette macros, and the 50-odd formerly static
functions the cut made cross-unit, declared where they are defined.
They keep their names; only the five units see the header.

One test moved with the code: test_portable_layouts' staleness check
greps the source for the layouts section, which now lives in
app_session.c.

Mechanical, so blame for anything in the four new files continues in
app.c before this commit.

0 files changed, 0 insertions, 0 deletions