feat(groups): optional forge source label in message footers

- Group.forgeLabel (default off, editable per group in the console) shows the
  source forge on every message the group's routes dispatch
- Discord embed footer: forge name next to the repo + the site's favicon as
  icon_url (Gitea instance's own favicon from its origin)
- Telegram footer: hyperlinked site name (GitHub or Gitea hostname); custom
  webhooks render a plain 'Custom' label
- forgeInfo() derives branding from event.provider + repository.html_url;
  dispatch attaches it to the NeutralMessage like mentionRoleIds
- validateGroups accepts forgeLabel booleans; GroupEditor gains the toggle
- tests: forgeInfo unit, discord/telegram footer render, dispatch on/off
- docs: groups.md + message-format.md (en/zh), config.example.yaml, AGENTS.md
- fix: wrangler.jsonc compatibility_date was an incomplete '2026-'

server/lib/drivers/telegram/render.ts

@@ -89,6 +89,10 @@ export function renderNeutralMessage(message: NeutralMessage): string {
   }
 
   const meta: string[] = [];
+  if (message.forge) {
+    const name = mdToHtml(message.forge.name);
+    meta.push(message.forge.url ? `<a href="${esc(message.forge.url)}">${name}</a>` : name);
+  }
   if (message.footer) meta.push(esc(message.footer));
   const ts = formatTimestamp(message.timestamp);
   if (ts) meta.push(ts);