DiscordChatExporter: exporting a Discord *forum* channel requires --include-threads

DiscordChatExporter.Cli (v2.47.3) cannot export a forum channel directly. dce export -c <forumChannelId> -f Json fails with: "Channel ... is a forum and cannot be exported directly. You need to pull its threads and export them individually."

Fix: pass --include-threads all (choices: None|Active|All). Then export -c <forumChannelId> --include-threads all -f Json --after <date> -o "dir/%c.json" enumerates every thread (each forum post = one thread) and writes one JSON per thread, named by %c (thread title/id).

Gotchas: 1) --after <date> filters MESSAGES, not threads. Thread enumeration still walks the entire forum history, so old threads with no recent messages still get exported (as near-empty files). Filter by last-activity timestamp in post-processing rather than trusting the file count. 2) dce channels -g <guild> --include-threads all (to list threads) is very slow and rate-limited across ALL channels in the guild, and only flushes stdout at the very end (0 output mid-run is normal, not a hang). If you just want one forum, skip the guild-wide listing and export the forum channel directly with --include-threads. 3) The exported JSON puts the THREAD TITLE in .channel.name (not a top-level title field); messages are in .messages[] with .author.name / .timestamp / .content.