chore: add global prettier ignore file

As prettier is not configured for this project, and the style doesn't
meet prettier's opinionated defaults, it's worth dropping this blanket
ignore until such a time (if ever) a prettier config is produced that
matches the styleguide of this project.

.editorconfig

@@ -0,0 +1,16 @@
+root = true
+
+[*]
+indent_style = tab
+tab_width = 3
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[*.json]
+indent_style = space
+indent_size = 2
+
+[*.md]
+trim_trailing_whitespace = false

.prettierignore

@@ -0,0 +1 @@
+*

.vscode/extensions.json

@@ -0,0 +1,5 @@
+{
+	"recommendations": [
+		"editorconfig.editorconfig"
+	]
+}

scripts/backfill.js

@@ -51,10 +51,24 @@ const preparedInsert = backfill.prepare("INSERT INTO backfill (channel_id, messa
 
 async function event(event) {
 	if (event.t !== "GUILD_CREATE") return
-	const channel = event.d.channels.find(c => c.id === channelID)
+	let channel = event.d.channels.find(c => c.id === channelID) || (event.d.threads || []).find(c => c.id === channelID)
-	if (!channel) return
 	const guild_id = event.d.id
 
+	if (!channel) {
+		// May be an archived thread not present in GUILD_CREATE data - try fetching via API
+		try {
+			const fetched = await discord.snow.channel.getChannel(channelID)
+			if (!fetched.guild_id || fetched.guild_id !== guild_id) return
+			fetched.guild_id = guild_id
+			discord.channels.set(fetched.id, fetched)
+			channel = fetched
+		} catch (e) {
+			return
+		}
+	}
+
+	if (!channel) return
+
 	try {
 		await createRoom.syncRoom(channelID)
 		let last = backfill.prepare("SELECT cast(max(message_id) as TEXT) FROM backfill WHERE channel_id = ?").pluck().get(channelID) || "0"