The bot no longer shells out to `opencode run`. Instead it POSTs to the
OpenAI-compatible /chat/completions endpoint exposed by llama-server on
halo.hoyer.tail:8000 directly. This removes the Bun/sqlite cold-start
overhead per request, drops the pkgs.opencode runtime dependency, and
eliminates the ExecStartPre dance that materialized config.json into the
service's $HOME.
Conversation history is now stored as a proper OpenAI `messages` list
with system/user/assistant roles, instead of the XML blob that was
inlined into a single `opencode run` argument. The interactive opencode
setup (config/opencode/config.json) is unchanged — only the bot stops
depending on it.
The module gains a `modelBaseUrl` option; `model` is now the bare model
name (`halo-8000`) without the provider/ prefix that the opencode CLI
required.
Mirrors the existing nextcloud-claude-bot setup but invokes `opencode run`
against the local `halo-8000` provider/model. The bot listens on
127.0.0.1:8086, is exposed via the `/_opencode-bot/` location on
nc.hoyer.xyz, and uses `@Halo` as its mention trigger in group chats.
The opencode config (config/opencode/config.json) is installed into the
service's $HOME/.config/opencode/ on each start, so the bot picks up the
same provider definition the user uses interactively. The model map keys
are renamed to `halo-8000` / `halo-8001` so the canonical
`provider/model` reference works without an alias indirection.
