feat(routing): add thread parent binding inheritance for Discord (#3892)

* feat(routing): add thread parent binding inheritance for Discord

When a Discord thread message doesn't match a direct peer binding,
now checks if the parent channel has a binding and uses that agent.

This enables multi-agent setups where threads inherit their parent
channel's agent binding automatically.

Changes:
- Add parentPeer parameter to ResolveAgentRouteInput
- Add binding.peer.parent match type
- Resolve thread parent early in Discord preflight
- Pass parentPeer to resolveAgentRoute for threads

Fixes thread routing in Discord multi-agent configurations where
threads were incorrectly routed to the default agent instead of
inheriting from their parent channel's binding.

* ci: trigger fresh macOS runners

* Discord: inherit thread bindings in reactions

* fix: add changelog for thread parent binding (#3892) (thanks @aerolalit)

---------

Co-authored-by: Lalit Singh <lalit@clawd.bot>
Co-authored-by: OSS Agent <oss-agent@clawdbot.ai>
Co-authored-by: Shadow <shadow@clawd.bot>

src/discord/monitor/native-command.ts

@@ -736,6 +736,7 @@ async function dispatchDiscordCommandInteraction(params: {
       kind: isDirectMessage ? "dm" : isGroupDm ? "group" : "channel",
       id: isDirectMessage ? user.id : channelId,
     },
+    parentPeer: threadParentId ? { kind: "channel", id: threadParentId } : undefined,
   });
   const conversationLabel = isDirectMessage ? (user.globalName ?? user.username) : channelId;
   const ctxPayload = finalizeInboundContext({