Discord referenced-message context drops embeds

[axsuul]

When a Discord workflow replies to a message whose useful content is stored in embeds, ${{ paseo.context }} includes the referenced message but drops the embeds.

A generic reproduction:

1. A bot or integration posts a Discord message with empty plain-text content and an embed containing a title, URL, description, or fields.
2. A user replies to that message and mentions Paseo.
3. The workflow includes ${{ paseo.context }} in its prompt.

The referenced message reaches the agent with empty content and no embed data, so the agent cannot understand what the user replied to.

Expected: referenced-message context includes normalized embed data such as title, description, URL, and fields.

Actual: normalizeContextMessage() copies content, author, attachments, and message references but does not copy message.embeds. This is unchanged in Hub v0.6.0 and current main.

Thread context uses the same normalization path, so embed-only messages lose their useful content there as well.

Related: #42 added direct referenced-message hydration.

[axsuul]

I found a second part of this while testing a patched Hub v0.6.0.

Preserving message.embeds fixes referenced messages that Hub already fetches. For thread mentions, Discord thread history may omit the message that created the thread. The starter can belong to the parent channel, so embed normalization alone is not enough.

We fixed it by fetching both sources:

const messages = await readThreadMessages(...);
const starter = await thread.fetchStarterMessage();

return {
  thread: {
    starter_message: materialize(starter),
    messages: materialize(messages),
  },
};

The implementation reuses the history result if it already contains the starter, so the message and its attachments are not duplicated. An Unknown Message response marks the starter unavailable, while permission and transport errors still propagate.

We patched our self-hosted Hub with this plus normalized embed fields and verified it against real embed-only Discord notifications. The agent received the starter title, description, URL, and fields through ${{ paseo.context }}.

Would you like me to submit a PR with the implementation and regression tests?