GetOnRenderToMain had grown to handle five distinct rendering cases inline (no
selection, submodule conflict, inline text conflict, non-textual text conflict,
and the normal working-tree diff), which made it hard to follow. Split each case
into its own method so the function reads as a short dispatcher, and pull the
repeated main-view boilerplate into renderToMainWithTask. Pure refactor; no
behavior change.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>