feat(bot): pick the target channel inside the announce modal

- The compose modal gains an optional channel select (text and
  announcement channels), preselected with the configured default
- /announce now posts only to the announce channel by default: the ops
  fallback is gone, so an unconfigured announce channel errors instead
  of silently posting to ops
- Roll call was already ops-only and is unchanged

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/bot/commands/announce.ts

@@ -1,7 +1,9 @@
 import {
-  ActionRowBuilder,
+  ChannelSelectMenuBuilder,
+  ChannelType,
   ComponentType,
   EmbedBuilder,
+  LabelBuilder,
   MessageFlags,
   ModalBuilder,
   SlashCommandBuilder,
@@ -20,6 +22,7 @@ const ANNOUNCE_COLOR = 0xf59e0b;
 const ANNOUNCE_MODAL_PREFIX = "ptf-announce:";
 const TITLE_INPUT_ID = "ptf-announce-title";
 const BODY_INPUT_ID = "ptf-announce-body";
+const CHANNEL_INPUT_ID = "ptf-announce-channel";
 /** Modal paragraph inputs cap at 4000 chars; the embed description limit is 4096. */
 const MAX_BODY_LENGTH = 4000;
 
@@ -33,6 +36,12 @@ const modalText = (fields: ModalSubmitInteraction["fields"], customId: string):
   return field?.type === ComponentType.TextInput ? field.value : "";
 };
 
+const modalChannelId = (fields: ModalSubmitInteraction["fields"]): string | null => {
+  const field = fields.fields.get(CHANNEL_INPUT_ID);
+  if (field?.type !== ComponentType.ChannelSelect) return null;
+  return field.channels?.first()?.id ?? null;
+};
+
 const postAnnouncement = async (
   channel: TextBasedChannelFields,
   title: string,
@@ -75,33 +84,33 @@ export const announceCommand: BotCommand = {
 
     const message = (interaction.options.getString("message") ?? "").trim();
     const option = interaction.options.getChannel("channel");
-    const channelId = option?.id ?? botConfig.announceChannelId ?? botConfig.opsChannelId;
+    const channelId = option?.id ?? botConfig.announceChannelId;
     if (!channelId) {
       await interaction.reply(
-        ephemeral("No announce channel is configured and no channel was given."),
+        ephemeral(
+          "No announce channel is configured (set DISCORD_ANNOUNCE_CHANNEL_ID) and no channel was given.",
+        ),
       );
       return;
     }
 
     if (!message) {
-      // Compose in a modal. The resolved channel rides along in the custom id,
-      // because modal submit interactions do not carry the command's options.
+      // customId carries the default channel as the fallback: modal submits
+      // don't carry the command's options.
       const modal = new ModalBuilder()
         .setCustomId(`${ANNOUNCE_MODAL_PREFIX}${channelId}`)
         .setTitle("Post an announcement");
-      modal.addComponents(
-        new ActionRowBuilder<TextInputBuilder>().addComponents(
+      modal.addLabelComponents(
+        new LabelBuilder().setLabel("Title (optional)").setTextInputComponent(
           new TextInputBuilder()
             .setCustomId(TITLE_INPUT_ID)
-            .setLabel("Title (optional)")
             .setStyle(TextInputStyle.Short)
             .setMaxLength(256)
             .setRequired(false),
         ),
-        new ActionRowBuilder<TextInputBuilder>().addComponents(
+        new LabelBuilder().setLabel("Announcement text").setTextInputComponent(
           new TextInputBuilder()
             .setCustomId(BODY_INPUT_ID)
-            .setLabel("Announcement text")
             .setStyle(TextInputStyle.Paragraph)
             .setMaxLength(MAX_BODY_LENGTH)
             .setRequired(true)
@@ -109,6 +118,16 @@ export const announceCommand: BotCommand = {
               "Paste your announcement. Markdown (headings, lists, bold, code) is supported.",
             ),
         ),
+        new LabelBuilder()
+          .setLabel("Channel (optional)")
+          .setDescription("Defaults to the configured app updates channel.")
+          .setChannelSelectMenuComponent(
+            new ChannelSelectMenuBuilder()
+              .setCustomId(CHANNEL_INPUT_ID)
+              .addChannelTypes(ChannelType.GuildText, ChannelType.GuildAnnouncement)
+              .setDefaultChannels(channelId)
+              .setRequired(false),
+          ),
       );
       await interaction.showModal(modal);
       return;
@@ -145,9 +164,11 @@ export const handleAnnounceModal = async (
     }
 
     // The modal custom id is "ptf-announce:<channelId>", written when the modal
-    // was opened from the slash command. Fall back to the configured channel.
+    // was opened. A channel picked in the modal overrides it.
     const customChannelId = interaction.customId.slice(ANNOUNCE_MODAL_PREFIX.length);
-    const resolvedId = customChannelId || botConfig.announceChannelId || botConfig.opsChannelId;
+    const resolvedId =
+      modalChannelId(interaction.fields) ??
+      (customChannelId || botConfig.announceChannelId);
     if (!resolvedId) {
       await interaction.reply(ephemeral("No announce channel is configured."));
       return;