fix(weixin): Stop auto-splitting messages by newlines; match Telegram behavior

[AaronWong1999]

Problem

The WeChat adapter splits every paragraph/line-break into a separate message, flooding users' chat interfaces. This behavior is unique to WeChat — the Telegram adapter keeps messages intact and only splits when exceeding the max length limit.

Users consistently reported this as a major UX pain point, especially for longer AI replies that get broken into 5-10 separate WeChat messages.

Solution

Two targeted changes to gateway/platforms/weixin.py:

1. _split_delivery_units_for_weixin — Simplified to return content as a single unit. Splitting is now handled by _split_text_for_weixin_delivery based on max_length (4000 chars) only.

2. _should_split_short_chat_block_for_weixin — Changed to return False. Previously, even with split_multiline_messages=false (the default), short 2-6 line messages would still be split into separate bubbles. This made the chat feel fragmented.

Impact

	Before	After
3-paragraph reply	3 separate WeChat messages	1 WeChat message
Short 4-line reply	4 bubbles	1 bubble
Long reply (>4000 chars)	Split by newlines + length	Split by length only (code blocks still intact)

Users who prefer the old per-line splitting behavior can still enable it via WEIXIN_SPLIT_MULTILINE_MESSAGES=true in their config.

Discovered by

This issue was discovered while building HermesClaw, a dual-proxy router that runs Hermes Agent and OpenClaw on the same WeChat account. The newline-splitting behavior was the #1 reported UX complaint from HermesClaw users.

Credit

• Discovered and fixed by Aaron Wong (@AaronWong1999)
• X/Twitter: @AaronYonW

Feel free to credit this contribution in the release notes or changelog. Happy to help the Hermes community! 🦞

[teknium1]

Merged via PR #8665 which synthesizes the best fixes from ~25 community PRs into a single consolidated change. Your contribution (stop auto-splitting by newlines) was reviewed and informed the final implementation. Thank you @AaronWong1999 for your work on this!