refactor!: rename chat providers to channels

src/channels/plugins/load.ts

@@ -0,0 +1,31 @@
+import type { ChannelId, ChannelPlugin } from "./types.js";
+
+type PluginLoader = () => Promise<ChannelPlugin>;
+
+// Channel docking: load *one* plugin on-demand.
+//
+// This avoids importing `src/channels/plugins/index.ts` (intentionally heavy)
+// from shared flows like outbound delivery / followup routing.
+const LOADERS: Record<ChannelId, PluginLoader> = {
+  telegram: async () => (await import("./telegram.js")).telegramPlugin,
+  whatsapp: async () => (await import("./whatsapp.js")).whatsappPlugin,
+  discord: async () => (await import("./discord.js")).discordPlugin,
+  slack: async () => (await import("./slack.js")).slackPlugin,
+  signal: async () => (await import("./signal.js")).signalPlugin,
+  imessage: async () => (await import("./imessage.js")).imessagePlugin,
+  msteams: async () => (await import("./msteams.js")).msteamsPlugin,
+};
+
+const cache = new Map<ChannelId, ChannelPlugin>();
+
+export async function loadChannelPlugin(
+  id: ChannelId,
+): Promise<ChannelPlugin | undefined> {
+  const cached = cache.get(id);
+  if (cached) return cached;
+  const loader = LOADERS[id];
+  if (!loader) return undefined;
+  const plugin = await loader();
+  cache.set(id, plugin);
+  return plugin;
+}