fix(discord): upload local video replies instead of printing the file:// path - #3289

What

Add ReplyType.VIDEO to the local-file branch of DiscordChannel._async_send, so a video reply whose content is a file:// path is uploaded through discord.File instead of falling through to the plain-text fallback.

Fixes #3288

Why

channel/chat_channel.py:418 produces Reply(ReplyType.VIDEO, f"file://{url}") for locally generated videos. QQ, wechatcom, weixin and wecom_bot all match ReplyType.VIDEO in their send paths; the Discord dispatch table only lists (VOICE, FILE), so the reply reaches the final else and the user gets the literal server path — file:///opt/cow/tmp/clip.mp4 — as a text bubble, with no video attached.

ReplyType.VIDEO_URL is untouched on purpose: Discord unfurls a bare URL into a player, so posting it as text is already correct.

Tests

tests/test_discord_video_reply.py stubs the discord module (it is imported lazily inside _async_send) and records what the channel sends:

• one test asserts a VIDEO reply uploads the path as a file and posts no text;
• one test pins the existing VIDEO_URL behaviour so the fix cannot regress URL unfurling.

On master, the first test fails with the bug reproduced:

AssertionError: video sent as a text bubble: ('file:///srv/cow/tmp/clip.mp4',) {}
1 failed, 1 passed

With the patch:

$ python -m pytest tests/test_discord_video_reply.py -q
2 passed in 0.40s

$ python -m pytest tests/ -q
36 failed, 2180 passed, 35 skipped, 55 subtests passed in 106.13s

The 36 failures are pre-existing: plain master at the same commit (c872f6f0) gives 36 failed, 2178 passed, 35 skipped, 55 subtests passed in 110.69s, the same failing set (test_scheduler_timezone, test_search_files_tool, test_security_read_env_bypass, …), none of it in the Discord channel. This branch adds exactly the two passing tests above.

The two extra lines in the diff

ruff (F-class gate) lints the Python files a PR changes, and channel/discord/discord_channel.py already carries two findings on master:

• F541 — a placeholder-free f-string at line 188;
• F841 — receiver = str(message.channel.id) at line 280, never read afterwards (context["receiver"] is set independently at line 263, and agent_router.resolve() takes only explicit_agent_id).

I cleared both so the gate stays green. They are pre-existing debt in this file, unrelated to the video bug.

$ ruff check channel/discord/discord_channel.py tests/test_discord_video_reply.py --select F --ignore F403,F405
All checks passed!