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/presets.lua

@@ -128,6 +128,9 @@ M.typst = {
   error_parser = function(output)
     return parse_typst(output)
   end,
+  clean = function(ctx)
+    return { 'rm', '-f', (ctx.file:gsub('%.typ$', '.pdf')) }
+  end,
   open = true,
   reload = function(ctx)
     return { 'typst', 'watch', ctx.file }
@@ -172,6 +175,10 @@ M.pdflatex = {
   error_parser = function(output)
     return parse_latexmk(output)
   end,
+  clean = function(ctx)
+    local base = ctx.file:gsub('%.tex$', '')
+    return { 'rm', '-f', base .. '.pdf', base .. '.aux', base .. '.log', base .. '.synctex.gz' }
+  end,
   open = true,
 }
 
@@ -188,6 +195,9 @@ M.tectonic = {
   error_parser = function(output)
     return parse_latexmk(output)
   end,
+  clean = function(ctx)
+    return { 'rm', '-f', (ctx.file:gsub('%.tex$', '.pdf')) }
+  end,
   open = true,
 }
 
@@ -246,7 +256,7 @@ M.asciidoctor = {
   ft = 'asciidoc',
   cmd = { 'asciidoctor' },
   args = function(ctx)
-    return { ctx.file, '-o', ctx.output }
+    return { '--failure-level', 'ERROR', ctx.file, '-o', ctx.output }
   end,
   output = function(ctx)
     return (ctx.file:gsub('%.adoc$', '.html'))