fix: describe command reopening log buffer without flicker

- Close terminal buffer before opening describe editor
  - Capture log state before closing to detect if we should reopen
  - Add on_unload callback to editor to handle log reopening
  - Suppress redraws during buffer transitions with lazyredraw
  - Remove duplicate hardcoded status keymaps from terminal.lua (were referencing undefined functions)
  - Fix resolve_keymaps_from_specs to validate handlers exist before creating keymaps

lua/jj/core/buffer.lua

@@ -297,4 +297,4 @@ function M.start_insert(buf)
 	vim.cmd("startinsert")
 end
 
-return M
+return M