fix(qqofficial): allocate fresh msg_seq per inbound msg_id (#2290)

[dadachann]

Summary

Fixes #2290. QQ Official v2 API deduplicates passive messages by (msg_id, msg_seq). The adapter reused msg_seq for multiple sends tied to the same inbound msg_id, so QQ rejected later sends with:

40054005 消息被去重，请检查请求msgseq

Three pre-existing strategies collided:

• Text (send_private_text_msg / send_group_text_msg): no msg_seq at all → QQ defaulted it to 1, so any 2nd text reply under the same msg_id was a duplicate.
• Rich media (_send_media_msg): used a global _msg_seq_counter — unique, but could still collide with the implicit msg_seq=1 of a text send under the same msg_id.
• Streaming (reply_message_chunk): msg_seq pinned at 1 forever, only index advanced → every chunk reused msg_seq=1 (the most frequent trigger).

Changes

• Add QQOfficialClient.next_reply_msg_seq(msg_id) — a per-inbound-msg_id allocator backed by a bounded OrderedDict (max 1024 keys, LRU eviction) + an asyncio.Lock for concurrency safety. No msg_id (proactive sends) falls back to the existing global counter.
• Wire it into C2C/group text sends and rich media.
• Streaming now advances ctx['msg_seq'] per chunk.
• Guild channel sends (send_channle_*) are intentionally left unchanged — they hit the legacy guild API, which does not use this dedup mechanism.

Tests

Added 3 regression tests to test_qqofficial_eba_adapter.py:

• allocator increments per msg_id, is independent across ids, falls back for missing id, and is gap-free under 50 concurrent allocations;
• multiple text replies under one inbound msg_id carry msg_seq 1, 2, 3;
• stream chunks emit strictly increasing, unique msg_seq.

All 12 tests in the file pass; ruff check and ruff format --check clean.

[dadachann]

CI 说明：当前红勾来自 base 分支 (dev/4.11.x) 的既有问题，与本 PR 无关

逐项核对：

Check	失败原因	是否本 PR 引入
Ruff Lint & Format	dev/4.11.x 上已有 48 个文件未通过 ruff format --check（涉及 slack / telegram / wecombot / agent-runner / alembic 等，本 PR 均未触碰）	否
Unit Tests 3.11/3.12/3.13	51 个 collection error，全部为 ModuleNotFoundError: No module named 'langbot_plugin.api.entities.builtin.agent_runner'，即 CI 解析到的 langbot_plugin 版本尚无该模块	否
E2E / Fast Integration	同上，import 阶段即失败	否
Frontend Lint	前端检查，与后端改动无关	否
Box Integration / CLA	✅ pass	—

验证：

• 直接 checkout 未带本改动的干净 origin/dev/4.11.x，执行 uv run ruff format src --check 同样报 48 files would be reformatted —— 基线本身即红。
• 本 PR 改动的 3 个文件单独跑 CI 同版本 ruff（0.14.14）：All checks passed + 3 files already formatted。
• 51 个 test collection error 中无任何 qqofficial 相关项；本 PR 新增的 3 个回归测试本地全部通过（12 passed）。

结论：本 PR 代码与测试本身可通过全部相关检查。待 dev/4.11.x 的格式化债与 langbot_plugin 版本问题在 base 修复后 rerun 即可转绿。