feat(discord): add configurable privileged Gateway Intents (GuildPresences, GuildMembers) (#2266)

* feat(discord): add configurable privileged Gateway Intents (GuildPresences, GuildMembers)

Add support for optionally enabling Discord privileged Gateway Intents
via config, starting with GuildPresences and GuildMembers.

When `channels.discord.intents.presence` is set to true:
- GatewayIntents.GuildPresences is added to the gateway connection
- A PresenceUpdateListener caches user presence data in memory
- The member-info action includes user status and activities
  (e.g. Spotify listening activity) from the cache

This enables use cases like:
- Seeing what music a user is currently listening to
- Checking user online/offline/idle/dnd status
- Tracking user activities through the bot API

Both intents require Portal opt-in (Discord Developer Portal →
Privileged Gateway Intents) before they can be used.

Changes:
- config: add `channels.discord.intents.{presence,guildMembers}`
- provider: compute intents dynamically from config
- listeners: add DiscordPresenceListener (extends PresenceUpdateListener)
- presence-cache: simple in-memory Map<userId, GatewayPresenceUpdate>
- discord-actions-guild: include cached presence in member-info response
- schema: add labels and descriptions for new config fields

* fix(test): add PresenceUpdateListener to @buape/carbon mock

* Discord: scope presence cache by account

---------

Co-authored-by: kugutsushi <kugutsushi@clawd>
Co-authored-by: Shadow <hi@shadowing.dev>

src/agents/tools/discord-actions-guild.ts

@@ -1,5 +1,6 @@
 import type { AgentToolResult } from "@mariozechner/pi-agent-core";
 import type { DiscordActionConfig } from "../../config/config.js";
+import { getPresence } from "../../discord/monitor/presence-cache.js";
 import {
   addRoleDiscord,
   createChannelDiscord,
@@ -54,7 +55,10 @@ export async function handleDiscordGuildAction(
       const member = accountId
         ? await fetchMemberInfoDiscord(guildId, userId, { accountId })
         : await fetchMemberInfoDiscord(guildId, userId);
-      return jsonResult({ ok: true, member });
+      const presence = getPresence(accountId, userId);
+      const activities = presence?.activities ?? undefined;
+      const status = presence?.status ?? undefined;
+      return jsonResult({ ok: true, member, ...(presence ? { status, activities } : {}) });
     }
     case "roleInfo": {
       if (!isActionEnabled("roleInfo")) {