use Oban for startup variant processing, add vips-heif

VariantCache now enqueues missing variants via OptimizeWorker instead
of processing directly with Task.async_stream. Simpler and uses the
existing job queue. Adds vips-heif to Docker runtime for HEIF support.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Dockerfile

@@ -87,7 +87,7 @@ RUN mix release
 FROM ${RUNNER_IMAGE} AS runner
 
 # Runtime deps only — no compilers, no -dev packages
-RUN apk add --no-cache libstdc++ openssl ncurses-libs vips
+RUN apk add --no-cache libstdc++ openssl ncurses-libs vips vips-heif
 
 WORKDIR /app
 

lib/berrypod/images/variant_cache.ex

@@ -75,33 +75,9 @@ defmodule Berrypod.Images.VariantCache do
     if to_process == [] do
       Logger.info("[VariantCache] All database image variants up to date")
     else
-      Logger.info(
+      Logger.info("[VariantCache] Enqueueing #{length(to_process)} images with missing variants")
-        "[VariantCache] Processing #{length(to_process)} images with missing variants..."
-      )
 
-      # Process directly instead of round-tripping through Oban — more reliable at startup
+      Enum.each(to_process, fn {id, _source_width} -> OptimizeWorker.enqueue(id) end)
-      to_process
-      |> Task.async_stream(
-        fn {id, _source_width} ->
-          case Optimizer.process_for_image(id) do
-            {:ok, _} ->
-              :ok
-
-            {:error, reason} ->
-              Logger.warning("[VariantCache] Failed to process #{id}: #{inspect(reason)}")
-          end
-        end,
-        max_concurrency: 4,
-        timeout: :timer.seconds(30),
-        on_timeout: :kill_task
-      )
-      |> Enum.count(fn
-        {:ok, :ok} -> true
-        _ -> false
-      end)
-      |> then(fn count ->
-        Logger.info("[VariantCache] Processed #{count}/#{length(to_process)} image variants")
-      end)
     end
   end