fix(romhacks): build on Alpine DCE base (apk + self-contained CLI)

The tyrrrz/discordchatexporter image is Alpine, not Debian, and ships DCE as a
self-contained executable (no dotnet on PATH). Use apk for python3 and invoke
/opt/app/DiscordChatExporter.Cli directly.

stacks/romhacks/orchestrator/Dockerfile

@@ -1,12 +1,12 @@
-# Orchestrator = DiscordChatExporter (has .NET + the DCE CLI) + Python for parsing.
+# Orchestrator = DiscordChatExporter (self-contained .NET CLI at
+# /opt/app/DiscordChatExporter.Cli) + Python3 for parsing. The DCE image is
+# Alpine-based, so install via apk. The parser uses only the stdlib (no pip deps).
 # Baking scripts + channels.json into the image avoids Portainer's relative
 # FILE-bind quirk (see docker-compose.yml header).
 FROM tyrrrz/discordchatexporter:stable
 
 USER root
-RUN apt-get update \
- && apt-get install -y --no-install-recommends python3 python3-requests \
- && rm -rf /var/lib/apt/lists/*
+RUN apk add --no-cache python3
 
 WORKDIR /app
 COPY orchestrate.py run.sh channels.json ./