feat: add Discord help command for servers and DMs

src/discord/help.ts

@@ -0,0 +1,22 @@
+import { commands } from './commands';
+import type { Reply } from './types';
+
+/** Use registration metadata so newly integrated commands appear automatically. */
+export function help(guild: boolean, origin: string): Reply {
+  return { type: 4, data: {
+    content: [
+      '**Minabot help**',
+      'Manage the same habits here and on the website. Commands work in servers and in DMs with the bot.',
+      '',
+      ...commands.map(command => `**/${command.name}** — ${command.description}`),
+      '',
+      'Start with /today, then choose a habit and use its buttons to record progress. Use the forms for amounts and other details.',
+      'If a control expires or progress changes elsewhere, run the command again to get fresh controls.',
+      '',
+      'Personal command replies in servers are visible only to you. Sharing progress requires an explicit sharing action.',
+    ].join('\n'),
+    ...(guild ? { flags: 64 } : {}),
+    allowed_mentions: { parse: [] },
+    components: [{ type: 1, components: [{ type: 2, style: 5, label: 'Open website', url: `${origin}/` }] }],
+  } };
+}