fix(telegram): include forward_from_chat metadata in forwarded message context (#8133)

Extract missing metadata from forwarded Telegram messages:

- Add fromChatType to TelegramForwardedContext, capturing the original
  chat type (channel/supergroup/group) from forward_from_chat.type
  and forward_origin.chat/sender_chat.type
- Add fromMessageId to capture the original message ID from channel forwards
- Read author_signature from forward_origin objects (modern API),
  preferring it over the deprecated forward_signature field
- Pass ForwardedFromChatType and ForwardedFromMessageId through to
  the inbound context payload
- Add test coverage for forward_origin channel/chat types, including
  author_signature extraction and fromChatType propagation

src/auto-reply/templating.ts

@@ -56,6 +56,8 @@ export type MsgContext = {
   ForwardedFromUsername?: string;
   ForwardedFromTitle?: string;
   ForwardedFromSignature?: string;
+  ForwardedFromChatType?: string;
+  ForwardedFromMessageId?: number;
   ForwardedDate?: number;
   ThreadStarterBody?: string;
   ThreadLabel?: string;