fix(discord): add missing type exports and fix unused imports

- Re-export DirectoryConfigParams and ChannelDirectoryEntry from channels/targets
- Remove unused ChannelDirectoryEntry and resolveDiscordAccount imports
- Fix parseDiscordTarget calls to not pass incompatible options type
- Fix unused catch parameter

Fixes CI build failures on main.

🤖 Generated with Claude Code

src/channels/targets.ts

@@ -1,3 +1,6 @@
+export type { DirectoryConfigParams } from "./plugins/directory-config.js";
+export type { ChannelDirectoryEntry } from "./plugins/types.js";
+
 export type MessagingTargetKind = "user" | "channel";
 
 export type MessagingTarget = {