Two independent robustness fixes:
1. ChatChannel.cancel_session / cancel_all_session raised KeyError when a
session existed in self.sessions but no future had been dispatched yet.
self.sessions[sid] is created in produce(), but self.futures[sid] is only
created later in consume() on first dispatch. Cancelling in that window
(e.g. user sends a message then immediately cancels) crashed the cancel
path. Use self.futures.get(sid, []) so an absent entry is a no-op.
2. compress_imgfile decremented JPEG quality by 5 with no lower bound. For an
image that cannot be compressed below max_size, quality went 0, negative,
... — the loop never terminated and passed invalid quality values to PIL.
Add a min_quality floor (10) and return the best effort once reached.
Adds tests/test_robustness_fixes.py covering both paths (5 tests).
- Clear NOT_SUPPORT_REPLYTYPE on weixin, wecom_bot, dingtalk so TTS replies
are actually synthesized for these channels.
- Wire desire_rtype=VOICE in weixin and wecom_bot _compose_context so the
always_reply_voice / voice_reply_voice toggles take effect.
- DingTalk: send native sampleAudio (mediaId + duration). The media API
only accepts ogg/amr, so convert TTS mp3/wav to amr on the fly.
- WeCom Bot: send native voice msgtype via ws (respond + active push),
converting TTS audio to amr before upload.
- Weixin (ilink): no outbound voice item, deliver TTS as a file attachment.
- chat_channel: when a TEXT reply is converted to VOICE, stash original
text in context["voice_reply_text"] and send a text bubble before the
voice reply. Skipped for feishu_streamed and wechatcom_app, which
already render text alongside the voice.
### Problem Description
When `context` is `None`, it should not be used for assignment operations.
### Solution
Adjusted the code logic to ensure that `context` is not `None` before performing any item assignment.
