fix(presets): add --failure-level ERROR to asciidoctor, add clean to typst/pdflatex/tectonic, skip auto-open on one-shot compile (#35)

Problem: asciidoctor exits 0 on errors so error_parser never ran.
typst, pdflatex, and tectonic had no clean subcommand. auto-open
fired on :Preview compile, surprising users who just want a build.

Solution: pass --failure-level ERROR in asciidoctor args. Add clean
commands to typst (rm pdf), pdflatex (rm pdf/aux/log/synctex.gz),
and tectonic (rm pdf). Gate auto-open on not opts.oneshot so it
only fires during toggle/watch mode.

lua/preview/compiler.lua

@@ -162,6 +162,7 @@ function M.compile(bufnr, name, provider, ctx, opts)
 
     if
       provider.open
+      and not opts.oneshot
       and not opened[bufnr]
       and output_file ~= ''
       and vim.uv.fs_stat(output_file)
@@ -240,6 +241,7 @@ function M.compile(bufnr, name, provider, ctx, opts)
         end
         if
           provider.open
+          and not opts.oneshot
           and not opened[bufnr]
           and output_file ~= ''
           and vim.uv.fs_stat(output_file)