Make docs optional in the tic80 updater

Older-style tic80 pipelines (bombexpert, mranderson) do not upload a
docs zip; the unconditional extraction raised and aborted the whole
update, so the new binary assets never got registered. Extract and
register docs only when the zip/dir exists. Covered by new
Tic80Service specs (optional docs + binary slug pickup).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

apps/api/app/services/software_updater/tic80_service.rb

@@ -4,9 +4,12 @@ module SoftwareUpdater
 
     private
 
+    # a docs opcionális: a régebbi sémájú tic80 pipeline-ok nem töltenek fel
+    # docs zipet, e nélkül is regisztrálni kell a többi assetet
     def prepare_files(versioned)
       extract_zip_to_dir("#{versioned}.html.zip", versioned)
-      extract_zip_to_dir("#{versioned}-docs.zip", "#{versioned}-docs")
+      docs_zip = "#{versioned}-docs.zip"
+      extract_zip_to_dir(docs_zip, "#{versioned}-docs") if File.file?(full_path(docs_zip))
     end
 
     def parse_metadata(versioned)
@@ -14,12 +17,14 @@ module SoftwareUpdater
     end
 
     def asset_paths(versioned)
-      {
+      paths = {
         "cartridge" => full_path("#{versioned}.tic"),
         "source"    => full_path("#{versioned}.lua"),
-        "html"      => full_path(versioned),
-        "docs"      => full_path("#{versioned}-docs")
+        "html"      => full_path(versioned)
       }
+      docs_dir = "#{versioned}-docs"
+      paths["docs"] = full_path(docs_dir) if dir_exists?(docs_dir)
+      paths
     end
 
     def parse_lua_metadata(source_path)