Never route videos through sendRichMessage - mobile black-screens them

Per Telegram's rich-messages spec (Bot API 10.1, released ~3 months before
this), our <video src="tg://video?id=..."> block syntax is exactly correct -
no documented issue with it. But isolated testing (posting the same
already-uploaded file both ways) proved the plain send_video call renders
fine on Telegram mobile in fullscreen, while the identical video referenced
from a sendRichMessage <video> block black-screens there every time. Neither
the faststart remux, the negative-DTS fix, nor the width/height fix changed
this - it's specifically the rich-message video renderer on mobile, not our
file.

sendRichMessage was only ever used for posts whose caption doesn't fit
Telegram's normal 1024-char limit; send_media_post already handles that
overflow correctly via follow-up text messages, so this isn't a regression
for long captions - it now always takes that path when a video is involved.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/tg_poster.py

@@ -481,7 +481,15 @@ class TelegramPoster:
         normal_limit = self.caption_limit if valid_media else self.message_limit
         fits_normal_limit = len(formatted_text) <= normal_limit
 
-        if valid_media and file_ids and not fits_normal_limit:
+        # Videos embedded as a <video> block in sendRichMessage (Bot API 10.1, a few
+        # months old at time of writing) reliably black-screen on Telegram mobile in
+        # fullscreen - confirmed against the actual failing post: the same file plays
+        # fine via the standard send_video call, so this isn't a problem with our
+        # encoding, it's the mobile client's rich-message video renderer. Route videos
+        # through the standard path unconditionally until that's fixed upstream.
+        has_video = any(m.media_type == "video" for m in valid_media)
+
+        if valid_media and file_ids and not fits_normal_limit and not has_video:
             rich_msg = self.build_rich_message(formatted_text, valid_media, file_ids)
             if rich_msg:
                 try: